Difference between revisions of "X86 microop ISA"
| (4 intermediate revisions by the same user not shown) | |||
| Line 1: | Line 1: | ||
= Register Ops = | = Register Ops = | ||
| + | |||
| + | These microops typically take two sources and produce one result. Most have a version that operates on only registers and a version which operates on registers and an immediate value. Some optionally set flags according to their operation. Some of them can be predicated. | ||
== Add == | == Add == | ||
| + | Addition. | ||
| + | |||
=== add Dest, Src1, Src2 === | === add Dest, Src1, Src2 === | ||
| − | Dest = Src1 + Src2 | + | Dest = Dest <- Src1 + Src2 |
Adds the contents of the Src1 and Src2 registers and puts the result in the Dest register. | Adds the contents of the Src1 and Src2 registers and puts the result in the Dest register. | ||
=== addi Dest, Src1, Imm === | === addi Dest, Src1, Imm === | ||
| − | Dest = Src1 + Imm | + | Dest = Dest <- Src1 + Imm |
Adds the contents of the Src1 register and the immediate Imm and puts the result in the Dest register. | Adds the contents of the Src1 register and the immediate Imm and puts the result in the Dest register. | ||
| Line 37: | Line 41: | ||
== Adc == | == Adc == | ||
| + | |||
| + | Add with carry. | ||
| + | |||
=== adc Dest, Src1, Src2 === | === adc Dest, Src1, Src2 === | ||
| − | Dest = Src1 + Src2 + CF | + | Dest = Dest <- Src1 + Src2 + CF |
Adds the contents of the Src1 and Src2 registers and the carry flag and puts the result in the Dest register. | Adds the contents of the Src1 and Src2 registers and the carry flag and puts the result in the Dest register. | ||
=== adci Dest, Src1, Imm === | === adci Dest, Src1, Imm === | ||
| − | Dest = Src1 + Imm + CF | + | Dest = Dest <- Src1 + Imm + CF |
Adds the contents of the Src1 register, the immediate Imm, and the carry flag and puts the result in the Dest register. | Adds the contents of the Src1 register, the immediate Imm, and the carry flag and puts the result in the Dest register. | ||
| Line 72: | Line 79: | ||
== Sub == | == Sub == | ||
| + | |||
| + | Subtraction. | ||
=== sub Dest, Src1, Src2 === | === sub Dest, Src1, Src2 === | ||
| − | Dest = Src1 - Src2 | + | Dest = Dest <- Src1 - Src2 |
Subtracts the contents of the Src2 register from the Src1 register and puts the result in the Dest register. | Subtracts the contents of the Src2 register from the Src1 register and puts the result in the Dest register. | ||
=== subi Dest, Src1, Imm === | === subi Dest, Src1, Imm === | ||
| − | Dest = Src1 - Imm | + | Dest = Dest <- Src1 - Imm |
Subtracts the contents of the immediate Imm from the Src1 register and puts the result in the Dest register. | Subtracts the contents of the immediate Imm from the Src1 register and puts the result in the Dest register. | ||
| Line 108: | Line 117: | ||
== Sbb == | == Sbb == | ||
| + | |||
| + | Subtract with barrow. | ||
=== sbb Dest, Src1, Src2 === | === sbb Dest, Src1, Src2 === | ||
| − | Dest = Src1 - Src2 - CF | + | Dest = Dest <- Src1 - Src2 - CF |
Subtracts the contents of the Src2 register and the carry flag from the Src1 register and puts the result in the Dest register. | Subtracts the contents of the Src2 register and the carry flag from the Src1 register and puts the result in the Dest register. | ||
=== sbbi Dest, Src1, Imm === | === sbbi Dest, Src1, Imm === | ||
| − | Dest = Src1 - Imm - CF | + | Dest = Dest <- Src1 - Imm - CF |
Subtracts the immediate Imm and the carry flag from the Src1 register and puts the result in the Dest register. | Subtracts the immediate Imm and the carry flag from the Src1 register and puts the result in the Dest register. | ||
| Line 144: | Line 155: | ||
== Mul1s == | == Mul1s == | ||
| + | |||
| + | Signed multiply. | ||
=== mul1s Src1, Src2 === | === mul1s Src1, Src2 === | ||
| Line 159: | Line 172: | ||
== Mul1u == | == Mul1u == | ||
| + | |||
| + | Unsigned multiply. | ||
=== mul1u Src1, Src2 === | === mul1u Src1, Src2 === | ||
| Line 174: | Line 189: | ||
== Mulel == | == Mulel == | ||
| + | |||
| + | Unload multiply result low. | ||
| + | |||
=== mulel Dest === | === mulel Dest === | ||
| − | Dest = ProdLo | + | Dest = Dest <- ProdLo |
Moves the value of the internal ProdLo register into the Dest register. | Moves the value of the internal ProdLo register into the Dest register. | ||
| Line 183: | Line 201: | ||
== Muleh == | == Muleh == | ||
| + | |||
| + | Unload multiply result high. | ||
=== muleh Dest === | === muleh Dest === | ||
| − | Dest = ProdHi | + | Dest = Dest <- ProdHi |
Moves the value of the internal ProdHi register into the Dest register. | Moves the value of the internal ProdHi register into the Dest register. | ||
| Line 202: | Line 222: | ||
== Div1 == | == Div1 == | ||
| + | |||
| + | First stage of division. | ||
=== div1 Src1, Src2 === | === div1 Src1, Src2 === | ||
| Line 219: | Line 241: | ||
== Div2 == | == Div2 == | ||
| + | |||
| + | Second and later stages of division. | ||
=== div2 Dest, Src1, Src2 === | === div2 Dest, Src1, Src2 === | ||
Quotient * Divisor + Remainder = original Remainder with bits shifted in from Src1 | Quotient * Divisor + Remainder = original Remainder with bits shifted in from Src1 | ||
| − | Dest = Src2 - number of bits shifted in above | + | Dest = Dest <- Src2 - number of bits shifted in above |
Performs subsequent steps of division following a div1 instruction. The contents of the register Src1 is the low portion of the dividend. The contents of the register Src2 denote the number of bits in Src1 that have not yet been used before this step in the division. Dest is set to the number of bits in Src1 that have not been used after this step. The internal registers Quotient, Divisor, and Remainder are updated by this instruction. | Performs subsequent steps of division following a div1 instruction. The contents of the register Src1 is the low portion of the dividend. The contents of the register Src2 denote the number of bits in Src1 that have not yet been used before this step in the division. Dest is set to the number of bits in Src1 that have not been used after this step. The internal registers Quotient, Divisor, and Remainder are updated by this instruction. | ||
| Line 232: | Line 256: | ||
Quotient * Divisor + Remainder = original Remainder with bits shifted in from Src1 | Quotient * Divisor + Remainder = original Remainder with bits shifted in from Src1 | ||
| − | Dest = Imm - number of bits shifted in above | + | Dest = Dest <- Imm - number of bits shifted in above |
Performs subsequent steps of division following a div1 instruction. The contents of the register Src1 is the low portion of the dividend. The immediate Imm denotes the number of bits in Src1 that have not yet been used before this step in the division. Dest is set to the number of bits in Src1 that have not been used after this step. The internal registers Quotient, Divisor, and Remainder are updated by this instruction. | Performs subsequent steps of division following a div1 instruction. The contents of the register Src1 is the low portion of the dividend. The immediate Imm denotes the number of bits in Src1 that have not yet been used before this step in the division. Dest is set to the number of bits in Src1 that have not been used after this step. The internal registers Quotient, Divisor, and Remainder are updated by this instruction. | ||
| Line 248: | Line 272: | ||
== Divq == | == Divq == | ||
| + | |||
| + | Unload division quotient. | ||
| + | |||
=== divq Dest === | === divq Dest === | ||
| − | Dest = Quotient | + | Dest = Dest <- Quotient |
Moves the value of the internal Quotient register into the Dest register. | Moves the value of the internal Quotient register into the Dest register. | ||
| Line 257: | Line 284: | ||
== Divr == | == Divr == | ||
| + | |||
| + | Unload division remainder. | ||
| + | |||
=== divr Dest === | === divr Dest === | ||
| − | Dest = Remainder | + | Dest = Dest <- Remainder |
Moves the value of the internal Remainder register into the Dest register. | Moves the value of the internal Remainder register into the Dest register. | ||
| Line 266: | Line 296: | ||
== Or == | == Or == | ||
| + | |||
| + | Logical or. | ||
| + | |||
=== or Dest, Src1, Src2 === | === or Dest, Src1, Src2 === | ||
| − | Dest = Src1 | Src2 | + | Dest = Dest <- Src1 | Src2 |
Computes the bitwise or of the contents of the Src1 and Src2 registers and puts the result in the Dest register. | Computes the bitwise or of the contents of the Src1 and Src2 registers and puts the result in the Dest register. | ||
=== ori Dest, Src1, Imm === | === ori Dest, Src1, Imm === | ||
| − | Dest = Src1 | Imm | + | Dest = Dest <- Src1 | Imm |
Computes the bitwise or of the contents of the Src1 register and the immediate Imm and puts the result in the Dest register. | Computes the bitwise or of the contents of the Src1 register and the immediate Imm and puts the result in the Dest register. | ||
| Line 302: | Line 335: | ||
== And == | == And == | ||
| + | |||
| + | Logical And | ||
| + | |||
=== and Dest, Src1, Src2 === | === and Dest, Src1, Src2 === | ||
| − | Dest = Src1 & Src2 | + | Dest = Dest <- Src1 & Src2 |
Computes the bitwise and of the contents of the Src1 and Src2 registers and puts the result in the Dest register. | Computes the bitwise and of the contents of the Src1 and Src2 registers and puts the result in the Dest register. | ||
=== andi Dest, Src1, Imm === | === andi Dest, Src1, Imm === | ||
| − | Dest = Src1 & Imm | + | Dest = Dest <- Src1 & Imm |
Computes the bitwise and of the contents of the Src1 register and the immediate Imm and puts the result in the Dest register. | Computes the bitwise and of the contents of the Src1 register and the immediate Imm and puts the result in the Dest register. | ||
| Line 338: | Line 374: | ||
== Xor == | == Xor == | ||
| + | |||
| + | Logical exclusive or. | ||
| + | |||
=== xor Dest, Src1, Src2 === | === xor Dest, Src1, Src2 === | ||
| − | Dest = Src1 | Src2 | + | Dest = Dest <- Src1 | Src2 |
Computes the bitwise xor of the contents of the Src1 and Src2 registers and puts the result in the Dest register. | Computes the bitwise xor of the contents of the Src1 and Src2 registers and puts the result in the Dest register. | ||
=== xori Dest, Src1, Imm === | === xori Dest, Src1, Imm === | ||
| − | Dest = Src1 | Imm | + | Dest = Dest <- Src1 | Imm |
Computes the bitwise xor of the contents of the Src1 register and the immediate Imm and puts the result in the Dest register. | Computes the bitwise xor of the contents of the Src1 register and the immediate Imm and puts the result in the Dest register. | ||
| Line 374: | Line 413: | ||
== Sll == | == Sll == | ||
| + | |||
| + | Logical left shift. | ||
| + | |||
=== sll Dest, Src1, Src2 === | === sll Dest, Src1, Src2 === | ||
| − | Dest = Src1 << Src2 | + | Dest = Dest <- Src1 << Src2 |
Shifts the contents of the Src1 register to the left by the value in the Src2 register and writes the result into the Dest register. The shift amount is truncated to either 5 or 6 bits, depending on the operand size. | Shifts the contents of the Src1 register to the left by the value in the Src2 register and writes the result into the Dest register. The shift amount is truncated to either 5 or 6 bits, depending on the operand size. | ||
=== slli Dest, Src1, Imm === | === slli Dest, Src1, Imm === | ||
| − | Dest = Src1 << Imm | + | Dest = Dest <- Src1 << Imm |
Shifts the contents of the Src1 register to the left by the value in the immediate Imm and writes the result into the Dest register. The shift amount is truncated to either 5 or 6 bits, depending on the operand size. | Shifts the contents of the Src1 register to the left by the value in the immediate Imm and writes the result into the Dest register. The shift amount is truncated to either 5 or 6 bits, depending on the operand size. | ||
| Line 397: | Line 439: | ||
== Srl == | == Srl == | ||
| + | |||
| + | Logical right shift. | ||
| + | |||
=== srl Dest, Src1, Src2 === | === srl Dest, Src1, Src2 === | ||
| − | Dest = Src1 >>(logical) Src2 | + | Dest = Dest <- Src1 >>(logical) Src2 |
Shifts the contents of the Src1 register to the right by the value in the Src2 register and writes the result into the Dest register. Bits which are shifted in sign extend the result. The shift amount is truncated to either 5 or 6 bits, depending on the operand size. | Shifts the contents of the Src1 register to the right by the value in the Src2 register and writes the result into the Dest register. Bits which are shifted in sign extend the result. The shift amount is truncated to either 5 or 6 bits, depending on the operand size. | ||
=== srli Dest, Src1, Imm === | === srli Dest, Src1, Imm === | ||
| − | Dest = Src1 >>(logical) Imm | + | Dest = Dest <- Src1 >>(logical) Imm |
Shifts the contents of the Src1 register to the right by the value in the immediate Imm and writes the result into the Dest register. Bits which are shifted in sign extend the result. The shift amount is truncated to either 5 or 6 bits, depending on the operand size. | Shifts the contents of the Src1 register to the right by the value in the immediate Imm and writes the result into the Dest register. Bits which are shifted in sign extend the result. The shift amount is truncated to either 5 or 6 bits, depending on the operand size. | ||
| Line 420: | Line 465: | ||
== Sra == | == Sra == | ||
| + | |||
| + | Arithmetic right shift. | ||
| + | |||
=== sra Dest, Src1, Src2 === | === sra Dest, Src1, Src2 === | ||
| − | Dest = Src1 >>(arithmetic) Src2 | + | Dest = Dest <- Src1 >>(arithmetic) Src2 |
Shifts the contents of the Src1 register to the right by the value in the Src2 register and writes the result into the Dest register. Bits which are shifted in zero extend the result. The shift amount is truncated to either 5 or 6 bits, depending on the operand size. | Shifts the contents of the Src1 register to the right by the value in the Src2 register and writes the result into the Dest register. Bits which are shifted in zero extend the result. The shift amount is truncated to either 5 or 6 bits, depending on the operand size. | ||
=== srai Dest, Src1, Imm === | === srai Dest, Src1, Imm === | ||
| − | Dest = Src1 >>(arithmetic) Imm | + | Dest = Dest <- Src1 >>(arithmetic) Imm |
Shifts the contents of the Src1 register to the right by the value in the immediate Imm and writes the result into the Dest register. Bits which are shifted in zero extend the result. The shift amount is truncated to either 5 or 6 bits, depending on the operand size. | Shifts the contents of the Src1 register to the right by the value in the immediate Imm and writes the result into the Dest register. Bits which are shifted in zero extend the result. The shift amount is truncated to either 5 or 6 bits, depending on the operand size. | ||
| Line 443: | Line 491: | ||
== Ror == | == Ror == | ||
| + | |||
| + | Rotate right. | ||
| + | |||
=== ror Dest, Src1, Src2 === | === ror Dest, Src1, Src2 === | ||
Rotates the contents of the Src1 register to the right by the value in the Src2 register and writes the result into the Dest register. The rotate amount is truncated to either 5 or 6 bits, depending on the operand size. | Rotates the contents of the Src1 register to the right by the value in the Src2 register and writes the result into the Dest register. The rotate amount is truncated to either 5 or 6 bits, depending on the operand size. | ||
| Line 462: | Line 513: | ||
== Rcr == | == Rcr == | ||
| + | |||
| + | Rotate right through carry. | ||
| + | |||
=== rcr Dest, Src1, Src2 === | === rcr Dest, Src1, Src2 === | ||
Rotates the contents of the Src1 register through the carry flag and to the right by the value in the Src2 register and writes the result into the Dest register. The rotate amount is truncated to either 5 or 6 bits, depending on the operand size. | Rotates the contents of the Src1 register through the carry flag and to the right by the value in the Src2 register and writes the result into the Dest register. The rotate amount is truncated to either 5 or 6 bits, depending on the operand size. | ||
| Line 481: | Line 535: | ||
== Rol == | == Rol == | ||
| + | |||
| + | Rotate left. | ||
| + | |||
=== rol Dest, Src1, Src2 === | === rol Dest, Src1, Src2 === | ||
Rotates the contents of the Src1 register to the left by the value in the Src2 register and writes the result into the Dest register. The rotate amount is truncated to either 5 or 6 bits, depending on the operand size. | Rotates the contents of the Src1 register to the left by the value in the Src2 register and writes the result into the Dest register. The rotate amount is truncated to either 5 or 6 bits, depending on the operand size. | ||
| Line 500: | Line 557: | ||
== Rcl == | == Rcl == | ||
| + | |||
| + | Rotate left through carry. | ||
| + | |||
=== rcl Dest, Src1, Src2 === | === rcl Dest, Src1, Src2 === | ||
Rotates the contents of the Src1 register through the carry flag and to the left by the value in the Src2 register and writes the result into the Dest register. The rotate amount is truncated to either 5 or 6 bits, depending on the operand size. | Rotates the contents of the Src1 register through the carry flag and to the left by the value in the Src2 register and writes the result into the Dest register. The rotate amount is truncated to either 5 or 6 bits, depending on the operand size. | ||
| Line 519: | Line 579: | ||
== Mov == | == Mov == | ||
| + | |||
| + | Move. | ||
| + | |||
=== mov Dest, Src1, Src2 === | === mov Dest, Src1, Src2 === | ||
| − | Dest = Src2 | + | Dest = Src1 <- Src2 |
| − | + | Merge the contents of the Src2 register into the contents of Src1 and put the result into the Dest register. | |
=== movi Dest, Src1, Imm === | === movi Dest, Src1, Imm === | ||
| − | Dest = Imm | + | Dest = Src1 <- Imm |
| − | + | Merge the contents of the immediate Imm into the contents of Src1 and put the results into the Dest register. | |
=== Flags === | === Flags === | ||
| Line 533: | Line 596: | ||
== Sext == | == Sext == | ||
| + | |||
| + | Sign extend. | ||
| + | |||
=== sext Dest, Src1, Imm === | === sext Dest, Src1, Imm === | ||
| − | Dest = sign_extend(Src1, Imm) | + | Dest = Dest <- sign_extend(Src1, Imm) |
Sign extend the value in the Src1 register starting at the bit position in the immediate Imm, and put the result in the Dest register. | Sign extend the value in the Src1 register starting at the bit position in the immediate Imm, and put the result in the Dest register. | ||
| Line 542: | Line 608: | ||
== Zext == | == Zext == | ||
| + | |||
| + | Zero extend. | ||
| + | |||
=== zext Dest, Src1, Imm === | === zext Dest, Src1, Imm === | ||
| − | Dest = zero_extend(Src1, Imm) | + | Dest = Dest <- zero_extend(Src1, Imm) |
Zero extend the value in the Src1 register starting at the bit position in the immediate Imm, and put the result in the Dest register. | Zero extend the value in the Src1 register starting at the bit position in the immediate Imm, and put the result in the Dest register. | ||
| Line 551: | Line 620: | ||
== Ruflag == | == Ruflag == | ||
| + | |||
| + | Read user flag. | ||
| + | |||
=== ruflag Dest, Imm === | === ruflag Dest, Imm === | ||
Reads the user level flag stored in the bit position specified by the immediate Imm and stores it in the register Dest. | Reads the user level flag stored in the bit position specified by the immediate Imm and stores it in the register Dest. | ||
| Line 595: | Line 667: | ||
== Ruflags == | == Ruflags == | ||
| + | |||
| + | Read all user flags. | ||
| + | |||
=== ruflags Dest === | === ruflags Dest === | ||
Dest = user flags | Dest = user flags | ||
| Line 604: | Line 679: | ||
== Wruflags == | == Wruflags == | ||
| + | |||
| + | Write all user flags. | ||
| + | |||
=== wruflags Src1, Src2 === | === wruflags Src1, Src2 === | ||
user flags = Src1 ^ Src2 | user flags = Src1 ^ Src2 | ||
| Line 617: | Line 695: | ||
See above. | See above. | ||
| − | == | + | == Rdip == |
| − | |||
| − | |||
| − | + | Read the instruction pointer. | |
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
=== rdip Dest === | === rdip Dest === | ||
Dest = rIP | Dest = rIP | ||
| Line 641: | Line 708: | ||
== Wrip == | == Wrip == | ||
| + | |||
| + | Write the instruction pointer. | ||
| + | |||
=== wrip Src1, Src2 === | === wrip Src1, Src2 === | ||
rIP = Src1 + Src2 | rIP = Src1 + Src2 | ||
| Line 653: | Line 723: | ||
=== Flags === | === Flags === | ||
This microop does not set any flags. It is optionally predicated. | This microop does not set any flags. It is optionally predicated. | ||
| + | |||
| + | == Chks == | ||
| + | Check selector. | ||
| + | |||
| + | Not yet implemented. | ||
= Load/Store Ops = | = Load/Store Ops = | ||
| + | |||
| + | == Ld == | ||
| + | Load. | ||
| + | === ld Data, Seg, Sib, Disp === | ||
| + | Loads the integer register Data from memory. | ||
| + | |||
| + | == Ldf == | ||
| + | Load floating point. | ||
| + | === ldf Data, Seg, Sib, Disp === | ||
| + | Loads the floating point register Data from memory. | ||
| + | |||
| + | == Ldm == | ||
| + | Load multimedia. | ||
| + | === ldm Data, Seg, Sib, Disp === | ||
| + | Load the multimedia register Data from memory. | ||
| + | This is not implemented and may never be. | ||
| + | |||
| + | == Ldst == | ||
| + | Load with store check. | ||
| + | === Ldst Data, Seg, Sib, Disp === | ||
| + | Load the integer register Data from memory while also checking if a store to that location would succeed. | ||
| + | This is not implemented currently. | ||
| + | |||
| + | == Ldstl == | ||
| + | Load with store check, locked. | ||
| + | === Ldst Data, Seg, Sib, Disp === | ||
| + | Load the integer register Data from memory while also checking if a store to that location would succeed, and also provide the semantics of the "LOCK" instruction prefix. | ||
| + | This is not implemented currently. | ||
| + | |||
| + | == St == | ||
| + | Store. | ||
| + | === st Data, Seg, Sib, Disp === | ||
| + | Stores the integer register Data to memory. | ||
| + | |||
| + | == Stf == | ||
| + | Store floating point. | ||
| + | === stf Data, Seg, Sib, Disp === | ||
| + | Stores the floating point register Data to memory. | ||
| + | |||
| + | == Stm == | ||
| + | Store multimedia. | ||
| + | === stm Data, Seg, Sib, Disp === | ||
| + | Store the multimedia register Data to memory. | ||
| + | This is not implemented and may never be. | ||
| + | |||
| + | == Stupd == | ||
| + | Store with base update. | ||
| + | === Stupd Data, Seg, Sib, Disp === | ||
| + | Store the integer register Data to memory and update the base register. | ||
| + | |||
| + | == Lea == | ||
| + | Load effective address. | ||
| + | === lea Data, Seg, Sib, Disp === | ||
| + | Calculates the address for this combination of parameters and stores it in Data. | ||
| + | |||
| + | == Cda == | ||
| + | Check data address. | ||
| + | === cda Seg, Sib, Disp === | ||
| + | Check whether the data address is valid. | ||
| + | This is not implemented currently. | ||
| + | |||
| + | == Cdaf == | ||
| + | CDA with cache line flush. | ||
| + | === cdaf Seg, Sib, Disp === | ||
| + | Check whether the data address is valid, and flush cache lines | ||
| + | This is not implemented currently. | ||
| + | |||
| + | == Cia == | ||
| + | Check instruction address. | ||
| + | === cia Seg, Sib, Disp === | ||
| + | Check whether the instruction address is valid. | ||
| + | This is not implemented currently. | ||
| + | |||
| + | == Tia == | ||
| + | TLB invalidate address | ||
| + | === tia Seg, Sib, Disp === | ||
| + | Invalidate the tlb entry which corresponds to this address. | ||
| + | This is not implemented currently. | ||
= Load immediate Op = | = Load immediate Op = | ||
| + | |||
| + | == Limm == | ||
| + | === limm Dest, Imm === | ||
| + | Stores the 64 bit immediate Imm into the integer register Dest. | ||
| + | |||
| + | = Floating Point Ops = | ||
| + | |||
| + | == Movfp == | ||
| + | === movfp Dest, Src === | ||
| + | Dest = Src | ||
| + | |||
| + | Move the contents of the floating point register Src into the floating point register Dest. | ||
| + | |||
| + | This instruction is predicated. | ||
| + | |||
| + | == Xorfp == | ||
| + | === xorfp Dest, Src1, Src2 === | ||
| + | Dest = Src1 ^ Src2 | ||
| + | |||
| + | Compute the bitwise exclusive or of the floating point registers Src1 and Src2 and put the result in the floating point register Dest. | ||
| + | |||
| + | == Sqrtfp == | ||
| + | === sqrtfp Dest, Src === | ||
| + | Dest = sqrt(Src) | ||
| + | |||
| + | Compute the square root of the floating point register Src and put the result in floating point register Dest. | ||
| + | |||
| + | == Addfp == | ||
| + | === addfp Dest, Src1, Src2 === | ||
| + | Dest = Src1 + Src2 | ||
| + | |||
| + | Compute the sum of the floating point registers Src1 and Src2 and put the result in the floating point register Dest. | ||
| + | |||
| + | == Subfp == | ||
| + | === subfp Dest, Src1, Src2 === | ||
| + | Dest = Src1 - Src2 | ||
| + | |||
| + | Compute the difference of the floating point registers Src1 and Src2 and put the result in the floating point register Dest. | ||
| + | |||
| + | == Mulfp == | ||
| + | === mulfp Dest, Src1, Src2 === | ||
| + | Dest = Src1 * Src2 | ||
| + | |||
| + | Compute the product of the floating point registers Src1 and Src2 and put the result in the floating point register Dest. | ||
| + | |||
| + | == Divfp == | ||
| + | === divfp Dest, Src1, Src2 === | ||
| + | Dest = Src1 / Src2 | ||
| + | |||
| + | Divide Src1 by Src2 and put the result in the floating point register Dest. | ||
| + | |||
| + | == Compfp == | ||
| + | === compfp Src1, Src2 === | ||
| + | Compare floating point registers Src1 and Src2. | ||
| + | |||
| + | == Cvtf_i2d == | ||
| + | === cvtf_i2d Dest, Src === | ||
| + | Convert integer register Src into a double floating point value and store the result in the lower part of Dest. | ||
| + | |||
| + | == Cvtf_i2d_hi == | ||
| + | === cvtf_i2d_hi Dest, Src === | ||
| + | Convert integer register Src into a double floating point value and store the result in the upper part of Dest. | ||
| + | |||
| + | == Cvtf_d2i == | ||
| + | === cvtf_d2i Dest, Src === | ||
| + | Convert floating point register Src into an integer value and store the result in the integer register Dest. | ||
| + | |||
| + | = Special Ops = | ||
| + | |||
| + | == Fault == | ||
| + | Generate a fault. | ||
| + | === fault fault_code === | ||
| + | Uses the C++ code fault_code to allocate a Fault object to return. | ||
| + | |||
| + | == Lddha == | ||
| + | Set the default handler for a fault. | ||
| + | This is not implemented currently. | ||
| + | |||
| + | == Ldaha == | ||
| + | Set the alternate handler for a fault | ||
| + | This is not implemented currently. | ||
| + | |||
| + | = Sequencing Ops = | ||
| + | These microops are used for control flow withing microcode | ||
| + | |||
| + | == Br == | ||
| + | |||
| + | Microcode branch. This is never considered the last microop of a sequence. If it appears at the end of a macroop, it is assumed that it branches to microcode in the ROM. | ||
| + | |||
| + | === br target === | ||
| + | micropc = target | ||
| + | |||
| + | Set the micropc to the 16 bit immediate target. | ||
| + | |||
| + | === Flags === | ||
| + | This microop does not set any flags. It is optionally predicated. | ||
| + | |||
| + | == Eret == | ||
| + | |||
| + | Return from emulation. This instruction is always considered the last microop in a sequence. When executing from the ROM, it is the only way to return to normal instruction decoding. | ||
| + | |||
| + | === eret === | ||
| + | |||
| + | Return from emulation. | ||
| + | |||
| + | === Flags === | ||
| + | This microop does not set any flags. It is optionally predicated. | ||
Latest revision as of 20:50, 21 September 2008
Contents
- 1 Register Ops
- 2 Load/Store Ops
- 3 Load immediate Op
- 4 Floating Point Ops
- 5 Special Ops
- 6 Sequencing Ops
Register Ops
These microops typically take two sources and produce one result. Most have a version that operates on only registers and a version which operates on registers and an immediate value. Some optionally set flags according to their operation. Some of them can be predicated.
Add
Addition.
add Dest, Src1, Src2
Dest = Dest <- Src1 + Src2
Adds the contents of the Src1 and Src2 registers and puts the result in the Dest register.
addi Dest, Src1, Imm
Dest = Dest <- Src1 + Imm
Adds the contents of the Src1 register and the immediate Imm and puts the result in the Dest register.
Flags
This microop optionally sets the CF, ECF, ZF, EZF, PF, AF, SF, and OF flags.
| CF and ECF | The carry out of the most significant bit. |
| ZF and EZF | Whether the result was zero. |
| PF | The parity of the result. |
| AF | The carry from the 4th to 5th bit positions. |
| SF | The sign of the result. |
| OF | Whether there was an overflow. |
Adc
Add with carry.
adc Dest, Src1, Src2
Dest = Dest <- Src1 + Src2 + CF
Adds the contents of the Src1 and Src2 registers and the carry flag and puts the result in the Dest register.
adci Dest, Src1, Imm
Dest = Dest <- Src1 + Imm + CF
Adds the contents of the Src1 register, the immediate Imm, and the carry flag and puts the result in the Dest register.
Flags
This microop optionally sets the CF, ECF, ZF, EZF, PF, AF, SF, and OF flags.
| CF and ECF | The carry out of the most significant bit. |
| ZF and EZF | Whether the result was zero. |
| PF | The parity of the result. |
| AF | The carry from the 4th to 5th bit positions. |
| SF | The sign of the result. |
| OF | Whether there was an overflow. |
Sub
Subtraction.
sub Dest, Src1, Src2
Dest = Dest <- Src1 - Src2
Subtracts the contents of the Src2 register from the Src1 register and puts the result in the Dest register.
subi Dest, Src1, Imm
Dest = Dest <- Src1 - Imm
Subtracts the contents of the immediate Imm from the Src1 register and puts the result in the Dest register.
Flags
This microop optionally sets the CF, ECF, ZF, EZF, PF, AF, SF, and OF flags.
| CF and ECF | The barrow into of the most significant bit. |
| ZF and EZF | Whether the result was zero. |
| PF | The parity of the result. |
| AF | The barrow from the 5th to 4th bit positions. |
| SF | The sign of the result. |
| OF | Whether there was an overflow. |
Sbb
Subtract with barrow.
sbb Dest, Src1, Src2
Dest = Dest <- Src1 - Src2 - CF
Subtracts the contents of the Src2 register and the carry flag from the Src1 register and puts the result in the Dest register.
sbbi Dest, Src1, Imm
Dest = Dest <- Src1 - Imm - CF
Subtracts the immediate Imm and the carry flag from the Src1 register and puts the result in the Dest register.
Flags
This microop optionally sets the CF, ECF, ZF, EZF, PF, AF, SF, and OF flags.
| CF and ECF | The barrow into of the most significant bit. |
| ZF and EZF | Whether the result was zero. |
| PF | The parity of the result. |
| AF | The barrow from the 5th to 4th bit positions. |
| SF | The sign of the result. |
| OF | Whether there was an overflow. |
Mul1s
Signed multiply.
mul1s Src1, Src2
ProdHi:ProdLo = Src1 * Src2
Multiplies the unsigned contents of the Src1 and Src2 registers and puts the high and low portions of the product into the internal registers ProdHi and ProdLo, respectively.
mul1si Src1, Imm
ProdHi:ProdLo = Src1 * Imm
Multiplies the unsigned contents of the Src1 register and the immediate Imm and puts the high and low portions of the product into the internal registers ProdHi and ProdLo, respectively.
Flags
This microop does not set any flags.
Mul1u
Unsigned multiply.
mul1u Src1, Src2
ProdHi:ProdLo = Src1 * Src2
Multiplies the unsigned contents of the Src1 and Src2 registers and puts the high and low portions of the product into the internal registers ProdHi and ProdLo, respectively.
mul1ui Src1, Imm
ProdHi:ProdLo = Src1 * Imm
Multiplies the unsigned contents of the Src1 register and the immediate Imm and puts the high and low portions of the product into the internal registers ProdHi and ProdLo, respectively.
Flags
This microop does not set any flags.
Mulel
Unload multiply result low.
mulel Dest
Dest = Dest <- ProdLo
Moves the value of the internal ProdLo register into the Dest register.
Flags
This microop does not set any flags.
Muleh
Unload multiply result high.
muleh Dest
Dest = Dest <- ProdHi
Moves the value of the internal ProdHi register into the Dest register.
Flags
This microop optionally sets the CF, ECF, and OF flags.
| CF and ECF | Whether ProdHi is non-zero |
| OF | Whether ProdHi is non-zero. |
Div1
First stage of division.
div1 Src1, Src2
Quotient * Src2 + Remainder = Src1 Divisor = Src2
Begins a division operation where the contents of SrcReg1 is the high part of the dividend and the contents of SrcReg2 is the divisor. The remainder from this partial division is put in the internal register Remainder. The quotient is put in the internal register Quotient. The divisor is put in the internal register Divisor.
div1i Src1, Imm:
Quotient * Imm + Remainder = Src1 Divisor = Imm
Begins a division operation where the contents of SrcReg1 is the high part of the dividend and the immediate Imm is the divisor. The remainder from this partial division is put in the internal register Remainder. The quotient is put in the internal register Quotient. The divisor is put in the internal register Divisor.
Flags
This microop does not set any flags.
Div2
Second and later stages of division.
div2 Dest, Src1, Src2
Quotient * Divisor + Remainder = original Remainder with bits shifted in from Src1
Dest = Dest <- Src2 - number of bits shifted in above
Performs subsequent steps of division following a div1 instruction. The contents of the register Src1 is the low portion of the dividend. The contents of the register Src2 denote the number of bits in Src1 that have not yet been used before this step in the division. Dest is set to the number of bits in Src1 that have not been used after this step. The internal registers Quotient, Divisor, and Remainder are updated by this instruction.
If there are no remaining bits in Src1, this instruction does nothing except optionally compute flags.
div2i Dest, Src1, Imm
Quotient * Divisor + Remainder = original Remainder with bits shifted in from Src1
Dest = Dest <- Imm - number of bits shifted in above
Performs subsequent steps of division following a div1 instruction. The contents of the register Src1 is the low portion of the dividend. The immediate Imm denotes the number of bits in Src1 that have not yet been used before this step in the division. Dest is set to the number of bits in Src1 that have not been used after this step. The internal registers Quotient, Divisor, and Remainder are updated by this instruction.
If there are no remaining bits in Src1, this instruction does nothing except optionally compute flags.
Flags
This microop optionally sets the EZF flag.
| EZF | Whether there are any remaining bits in Src1 after this step. |
Divq
Unload division quotient.
divq Dest
Dest = Dest <- Quotient
Moves the value of the internal Quotient register into the Dest register.
Flags
This microop does not set any flags.
Divr
Unload division remainder.
divr Dest
Dest = Dest <- Remainder
Moves the value of the internal Remainder register into the Dest register.
Flags
This microop does not set any flags.
Or
Logical or.
or Dest, Src1, Src2
Dest = Dest <- Src1 | Src2
Computes the bitwise or of the contents of the Src1 and Src2 registers and puts the result in the Dest register.
ori Dest, Src1, Imm
Dest = Dest <- Src1 | Imm
Computes the bitwise or of the contents of the Src1 register and the immediate Imm and puts the result in the Dest register.
Flags
This microop optionally sets the CF, ECF, ZF, EZF, PF, AF, SF, and OF flags. There is nothing that prevents computing a value for the AF flag, but it's value will be meaningless.
| CF and ECF | Cleared |
| ZF and EZF | Whether the result was zero. |
| PF | The parity of the result. |
| AF | Undefined |
| SF | The sign of the result. |
| OF | Cleared |
And
Logical And
and Dest, Src1, Src2
Dest = Dest <- Src1 & Src2
Computes the bitwise and of the contents of the Src1 and Src2 registers and puts the result in the Dest register.
andi Dest, Src1, Imm
Dest = Dest <- Src1 & Imm
Computes the bitwise and of the contents of the Src1 register and the immediate Imm and puts the result in the Dest register.
Flags
This microop optionally sets the CF, ECF, ZF, EZF, PF, AF, SF, and OF flags. There is nothing that prevents computing a value for the AF flag, but it's value will be meaningless.
| CF and ECF | Cleared |
| ZF and EZF | Whether the result was zero. |
| PF | The parity of the result. |
| AF | Undefined |
| SF | The sign of the result. |
| OF | Cleared |
Xor
Logical exclusive or.
xor Dest, Src1, Src2
Dest = Dest <- Src1 | Src2
Computes the bitwise xor of the contents of the Src1 and Src2 registers and puts the result in the Dest register.
xori Dest, Src1, Imm
Dest = Dest <- Src1 | Imm
Computes the bitwise xor of the contents of the Src1 register and the immediate Imm and puts the result in the Dest register.
Flags
This microop optionally sets the CF, ECF, ZF, EZF, PF, AF, SF, and OF flags. There is nothing that prevents computing a value for the AF flag, but it's value will be meaningless.
| CF and ECF | Cleared |
| ZF and EZF | Whether the result was zero. |
| PF | The parity of the result. |
| AF | Undefined |
| SF | The sign of the result. |
| OF | Cleared |
Sll
Logical left shift.
sll Dest, Src1, Src2
Dest = Dest <- Src1 << Src2
Shifts the contents of the Src1 register to the left by the value in the Src2 register and writes the result into the Dest register. The shift amount is truncated to either 5 or 6 bits, depending on the operand size.
slli Dest, Src1, Imm
Dest = Dest <- Src1 << Imm
Shifts the contents of the Src1 register to the left by the value in the immediate Imm and writes the result into the Dest register. The shift amount is truncated to either 5 or 6 bits, depending on the operand size.
Flags
This microop optionally sets the CF, ECF, and OF flags. If the shift amount is zero, no flags are modified.
| CF and ECF | The last bit shifted out of the result. |
| OF | The exclusive or of the what this instruction would set the CF flag to (if requested) and the most significant bit of the result |
Srl
Logical right shift.
srl Dest, Src1, Src2
Dest = Dest <- Src1 >>(logical) Src2
Shifts the contents of the Src1 register to the right by the value in the Src2 register and writes the result into the Dest register. Bits which are shifted in sign extend the result. The shift amount is truncated to either 5 or 6 bits, depending on the operand size.
srli Dest, Src1, Imm
Dest = Dest <- Src1 >>(logical) Imm
Shifts the contents of the Src1 register to the right by the value in the immediate Imm and writes the result into the Dest register. Bits which are shifted in sign extend the result. The shift amount is truncated to either 5 or 6 bits, depending on the operand size.
Flags
This microop optionally sets the CF, ECF, and OF flags. If the shift amount is zero, no flags are modified.
| CF and ECF | The last bit shifted out of the result. |
| OF | The most significant bit of the original value to shift |
Sra
Arithmetic right shift.
sra Dest, Src1, Src2
Dest = Dest <- Src1 >>(arithmetic) Src2
Shifts the contents of the Src1 register to the right by the value in the Src2 register and writes the result into the Dest register. Bits which are shifted in zero extend the result. The shift amount is truncated to either 5 or 6 bits, depending on the operand size.
srai Dest, Src1, Imm
Dest = Dest <- Src1 >>(arithmetic) Imm
Shifts the contents of the Src1 register to the right by the value in the immediate Imm and writes the result into the Dest register. Bits which are shifted in zero extend the result. The shift amount is truncated to either 5 or 6 bits, depending on the operand size.
Flags
This microop optionally sets the CF, ECF, and OF flags. If the shift amount is zero, no flags are modified.
| CF and ECF | The last bit shifted out of the result. |
| OF | Cleared |
Ror
Rotate right.
ror Dest, Src1, Src2
Rotates the contents of the Src1 register to the right by the value in the Src2 register and writes the result into the Dest register. The rotate amount is truncated to either 5 or 6 bits, depending on the operand size.
rori Dest, Src1, Imm
Rotates the contents of the Src1 register to the right by the value in the immediate Imm and writes the result into the Dest register. The rotate amount is truncated to either 5 or 6 bits, depending on the operand size.
Flags
This microop optionally sets the CF, ECF, and OF flags. If the rotate amount is zero, no flags are modified.
| CF and ECF | The most significant bit of the result. |
| OF | The exclusive or of the two most significant bits of the original value. |
Rcr
Rotate right through carry.
rcr Dest, Src1, Src2
Rotates the contents of the Src1 register through the carry flag and to the right by the value in the Src2 register and writes the result into the Dest register. The rotate amount is truncated to either 5 or 6 bits, depending on the operand size.
rcri Dest, Src1, Imm
Rotates the contents of the Src1 register through the carry flag and to the right by the value in the immediate Imm and writes the result into the Dest register. The rotate amount is truncated to either 5 or 6 bits, depending on the operand size.
Flags
This microop optionally sets the CF, ECF, and OF flags. If the rotate amount is zero, no flags are modified.
| CF and ECF | The last bit shifted out of the result. |
| OF | The exclusive or of the CF flag before the rotate and the most significant bit of the original value. |
Rol
Rotate left.
rol Dest, Src1, Src2
Rotates the contents of the Src1 register to the left by the value in the Src2 register and writes the result into the Dest register. The rotate amount is truncated to either 5 or 6 bits, depending on the operand size.
roli Dest, Src1, Imm
Rotates the contents of the Src1 register to the left by the value in the immediate Imm and writes the result into the Dest register. The rotate amount is truncated to either 5 or 6 bits, depending on the operand size.
Flags
This microop optionally sets the CF, ECF, and OF flags. If the rotate amount is zero, no flags are modified.
| CF and ECF | The least significant bit of the result. |
| OF | The exclusive or of the most and least significant bits of the result. |
Rcl
Rotate left through carry.
rcl Dest, Src1, Src2
Rotates the contents of the Src1 register through the carry flag and to the left by the value in the Src2 register and writes the result into the Dest register. The rotate amount is truncated to either 5 or 6 bits, depending on the operand size.
rcli Dest, Src1, Imm
Rotates the contents of the Src1 register through the carry flag and to the left by the value in the immediate Imm and writes the result into the Dest register. The rotate amount is truncated to either 5 or 6 bits, depending on the operand size.
Flags
This microop optionally sets the CF, ECF, and OF flags. If the rotate amount is zero, no flags are modified.
| CF and ECF | The last bit rotated out of the result. |
| OF | The exclusive or of CF before the rotate and most significant bit of the result. |
Mov
Move.
mov Dest, Src1, Src2
Dest = Src1 <- Src2
Merge the contents of the Src2 register into the contents of Src1 and put the result into the Dest register.
movi Dest, Src1, Imm
Dest = Src1 <- Imm
Merge the contents of the immediate Imm into the contents of Src1 and put the results into the Dest register.
Flags
This microop does not set any flags. It is optionally predicated.
Sext
Sign extend.
sext Dest, Src1, Imm
Dest = Dest <- sign_extend(Src1, Imm)
Sign extend the value in the Src1 register starting at the bit position in the immediate Imm, and put the result in the Dest register.
Flags
This microop does not set any flags.
Zext
Zero extend.
zext Dest, Src1, Imm
Dest = Dest <- zero_extend(Src1, Imm)
Zero extend the value in the Src1 register starting at the bit position in the immediate Imm, and put the result in the Dest register.
Flags
This microop does not set any flags.
Ruflag
Read user flag.
ruflag Dest, Imm
Reads the user level flag stored in the bit position specified by the immediate Imm and stores it in the register Dest.
The mapping between values of Imm and user level flags is show in the following table.
| 0 | CF (carry flag) |
| 2 | PF (parity flag) |
| 3 | ECF (emulation carry flag) |
| 4 | AF (auxiliary carry flag) |
| 5 | EZF (emulation zero flag) |
| 6 | ZF (zero flag) |
| 7 | SF (sign flag) |
| 10 | DF (direction flag) |
| 11 | OF (overflow flag) |
Flags
The EZF flag is always set. In the future this may become optional.
| EZF | Set if the value of the flag read was zero. |
Ruflags
Read all user flags.
ruflags Dest
Dest = user flags
Store the user level flags into the Dest register.
Flags
This microop does not set any flags.
Wruflags
Write all user flags.
wruflags Src1, Src2
user flags = Src1 ^ Src2
Set the user level flags to the exclusive or of the Src1 and Src2 registers.
wruflagsi Src1, Imm
user flags = Src1 ^ Imm
Set the user level flags to the exclusive or of the Src1 register and the immediate Imm.
Flags
See above.
Rdip
Read the instruction pointer.
rdip Dest
Dest = rIP
Set the Dest register to the current value of rIP.
Flags
This microop does not set any flags.
Wrip
Write the instruction pointer.
wrip Src1, Src2
rIP = Src1 + Src2
Set the rIP to the sum of the Src1 and Src2 registers. This causes a macroop branch at the end of the current macroop.
wripi Src1, Imm
micropc = Src1 + Imm
Set the rIP to the sum of the Src1 register and immediate Imm. This causes a macroop branch at the end of the current macroop.
Flags
This microop does not set any flags. It is optionally predicated.
Chks
Check selector.
Not yet implemented.
Load/Store Ops
Ld
Load.
ld Data, Seg, Sib, Disp
Loads the integer register Data from memory.
Ldf
Load floating point.
ldf Data, Seg, Sib, Disp
Loads the floating point register Data from memory.
Ldm
Load multimedia.
ldm Data, Seg, Sib, Disp
Load the multimedia register Data from memory. This is not implemented and may never be.
Ldst
Load with store check.
Ldst Data, Seg, Sib, Disp
Load the integer register Data from memory while also checking if a store to that location would succeed. This is not implemented currently.
Ldstl
Load with store check, locked.
Ldst Data, Seg, Sib, Disp
Load the integer register Data from memory while also checking if a store to that location would succeed, and also provide the semantics of the "LOCK" instruction prefix. This is not implemented currently.
St
Store.
st Data, Seg, Sib, Disp
Stores the integer register Data to memory.
Stf
Store floating point.
stf Data, Seg, Sib, Disp
Stores the floating point register Data to memory.
Stm
Store multimedia.
stm Data, Seg, Sib, Disp
Store the multimedia register Data to memory. This is not implemented and may never be.
Stupd
Store with base update.
Stupd Data, Seg, Sib, Disp
Store the integer register Data to memory and update the base register.
Lea
Load effective address.
lea Data, Seg, Sib, Disp
Calculates the address for this combination of parameters and stores it in Data.
Cda
Check data address.
cda Seg, Sib, Disp
Check whether the data address is valid. This is not implemented currently.
Cdaf
CDA with cache line flush.
cdaf Seg, Sib, Disp
Check whether the data address is valid, and flush cache lines This is not implemented currently.
Cia
Check instruction address.
cia Seg, Sib, Disp
Check whether the instruction address is valid. This is not implemented currently.
Tia
TLB invalidate address
tia Seg, Sib, Disp
Invalidate the tlb entry which corresponds to this address. This is not implemented currently.
Load immediate Op
Limm
limm Dest, Imm
Stores the 64 bit immediate Imm into the integer register Dest.
Floating Point Ops
Movfp
movfp Dest, Src
Dest = Src
Move the contents of the floating point register Src into the floating point register Dest.
This instruction is predicated.
Xorfp
xorfp Dest, Src1, Src2
Dest = Src1 ^ Src2
Compute the bitwise exclusive or of the floating point registers Src1 and Src2 and put the result in the floating point register Dest.
Sqrtfp
sqrtfp Dest, Src
Dest = sqrt(Src)
Compute the square root of the floating point register Src and put the result in floating point register Dest.
Addfp
addfp Dest, Src1, Src2
Dest = Src1 + Src2
Compute the sum of the floating point registers Src1 and Src2 and put the result in the floating point register Dest.
Subfp
subfp Dest, Src1, Src2
Dest = Src1 - Src2
Compute the difference of the floating point registers Src1 and Src2 and put the result in the floating point register Dest.
Mulfp
mulfp Dest, Src1, Src2
Dest = Src1 * Src2
Compute the product of the floating point registers Src1 and Src2 and put the result in the floating point register Dest.
Divfp
divfp Dest, Src1, Src2
Dest = Src1 / Src2
Divide Src1 by Src2 and put the result in the floating point register Dest.
Compfp
compfp Src1, Src2
Compare floating point registers Src1 and Src2.
Cvtf_i2d
cvtf_i2d Dest, Src
Convert integer register Src into a double floating point value and store the result in the lower part of Dest.
Cvtf_i2d_hi
cvtf_i2d_hi Dest, Src
Convert integer register Src into a double floating point value and store the result in the upper part of Dest.
Cvtf_d2i
cvtf_d2i Dest, Src
Convert floating point register Src into an integer value and store the result in the integer register Dest.
Special Ops
Fault
Generate a fault.
fault fault_code
Uses the C++ code fault_code to allocate a Fault object to return.
Lddha
Set the default handler for a fault. This is not implemented currently.
Ldaha
Set the alternate handler for a fault This is not implemented currently.
Sequencing Ops
These microops are used for control flow withing microcode
Br
Microcode branch. This is never considered the last microop of a sequence. If it appears at the end of a macroop, it is assumed that it branches to microcode in the ROM.
br target
micropc = target
Set the micropc to the 16 bit immediate target.
Flags
This microop does not set any flags. It is optionally predicated.
Eret
Return from emulation. This instruction is always considered the last microop in a sequence. When executing from the ROM, it is the only way to return to normal instruction decoding.
eret
Return from emulation.
Flags
This microop does not set any flags. It is optionally predicated.
