X86 microop ISA

Register Ops

Add

add: Dest = Src1 + Src2

Adds the contents of the Src1 and Src2 registers and puts the result in the Dest register.

addi: 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

adc: 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 + 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

sub: 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

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

sbb: 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 - 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

mul1s: 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: 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

mul1u: 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: 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

mulel: Dest = ProdLo

Moves the value of the internal ProdLo register into the Dest register.

Flags

This microop does not set any flags.

Muleh

muleh: 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

div1

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: Quotient * Src1 + Remainder = Src1

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

div2

Quotient * Divisor + Remainder = original Remainder with bits shifted in from Src1 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

Quotient * Divisor + Remainder = original Remainder with bits shifted in from Src1 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

divq: Dest = Quotient

Moves the value of the internal Quotient register into the Dest register.

Flags

This microop does not set any flags.

Divr

divr: Dest = Remainder

Moves the value of the internal Remainder register into the Dest register.

Flags

This microop does not set any flags.

Or

or: 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

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

and: 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

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

xor: 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

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

sll: 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

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

srl: 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 >>(logical) Src2

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

sra: 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 >>(arithmetic) Src2

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