PMULDQ

Multiply Packed Signed Dword Integers

Opcodes

Hex Mnemonic Encoding Long Mode Legacy Mode Description
66 0F 38 28 /r PMULDQ xmm1, xmm2/m128 A Valid Valid Multiply the packed signed dword integers in xmm1 and xmm2/m128 and store the quadword product in xmm1.

Instruction Operand Encoding

Op/En Operand 0 Operand 1 Operand 2 Operand 3
A NA NA ModRM:r/m (r) ModRM:reg (r, w)

Description

Performs two signed multiplications from two pairs of signed dword integers and stores two 64-bit products in the destination operand (first operand). The 64-bit product from the first/third dword element in the destination operand and the first/third dword element of the source operand (second operand) is stored to the low/high qword element of the destination.

If the source is a memory operand then all 128 bits will be fetched from memory but the second and fourth dwords will not be used in the computation.

Pseudo Code

DEST[63:0] = DEST[31:0] * SRC[31:0];
DEST[127:64] = DEST[95:64] * SRC[95:64];

Flags Affected

None

Exceptions

64-Bit Mode Exceptions

Exception Description
#UD If EM in CR0 is set. If OSFXSR in CR4 is 0. If CPUID feature flag ECX.SSE4_1 is 0. If LOCK prefix is used. Either the prefix REP (F3h) or REPN (F2H) is used.
#NM If TS in CR0 is set.
#PF(fault-code) For a page fault.
#SS(0) If a memory address referencing the SS segment is in a non- canonical form.
#GP(0) If the memory address is in a non-canonical form. If a memory operand is not aligned on a 16-byte boundary, regardless of segment.

Compatibility Mode Exceptions

Same exceptions as in Protected Mode.

Virtual-8086 Mode Exceptions

Exception Description
#PF(fault-code) For a page fault.
Same exceptions as in Real Address Mode.

Real-Address Mode Exceptions

Exception Description
#UD If CR0.EM[bit 2] = 1. If CR4.OSFXSR[bit 9] = 0. If CPUID.01H:ECX.SSE4_1[bit 19] = 0. If LOCK prefix is used. Either the prefix REP (F3h) or REPN (F2H) is used.
#NM If CR0.TS[bit 3] = 1.
#GP(0) if any part of the operand lies outside of the effective address space from 0 to 0FFFFH. If a memory operand is not aligned on a 16-byte boundary, regardless of segment.

Protected Mode Exceptions

Exception Description
#UD If CR0.EM[bit 2] = 1. If CR4.OSFXSR[bit 9] = 0. If CPUID.01H:ECX.SSE4_1[bit 19] = 0. If LOCK prefix is used. Either the prefix REP (F3h) or REPN (F2H) is used.
#NM If CR0.TS[bit 3] = 1.
#PF(fault-code) For a page fault.
#SS(0) For an illegal address in the SS segment.
#GP(0) For an illegal memory operand effective address in the CS, DS, ES, FS, or GS segments. If a memory operand is not aligned on a 16-byte boundary, regardless of segment.