Intel ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS VOLUME 3 REV 2.3, Manual

Page: 1703 / 1898

Volume 4: IA-32 Intel
®
MMX™ Technology Instruction Reference 4:401
MOVD—Move 32 Bits
Description
Copies doubleword from the source operand (second operand) to the destination
operand (first operand). Source and destination operands can be MMX technology
registers, memory locations, or 32-bit general-purpose registers; however, data cannot
be transferred from an MMX technology register to an MMX technology register, from
one memory location to another memory location, or from one general-purpose register
to another general-purpose register.
When the destination operand is an MMX technology register, the 32-bit source value is
written to the low-order 32 bits of the 64-bit MMX technology register and
zero-extended to 64 bits (see
Figure 3-1 ). When the source operand is an MMX
technology register, the low-order 32 bits of the MMX technology register are written to
the 32-bit general-purpose register or 32-bit memory location selected with the
destination operand.
Operation
IF DEST is MMX register
THEN
DEST

ZeroExtend(SRC);
ELSE (* SRC is MMX register *)
DEST

LowOrderDoubleword(SRC);
Opcode Instruction Description
0F 6E /r MOVD mm, r/m32 Move doubleword from r/m32 to mm .
0F 7E /r MOVD r/m32, mm Move doubleword from mm to r/m32 .
Figure 3-1. Operation of the MOVD Instruction
3006010
MOVD m32, mm
MOVD mm, r32
63
31 0
32 31
mm
m32
15 0
0
00000000
b b b b r32
b b b b
63
mm
0
xxxxxxxx b b b
b b
b b
W
W
32 31
3 2 1 0
3
0 1
2
N+1
N+1
3 2 1 0
b
3 2 1 0