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Source code

PHMINPOSUW

Packed Horizontal Word Minimum

stableVMJITAOTinstruction

Encodings

OpcodeInstructionOp/En64-bitCompat/LegacyDescription
66 0F 38 41 /rPHMINPOSUW xmm1, xmm2/m128RMValidValidFind the minimum unsigned word in xmm2/m128 and place its value in the low word of xmm1 and its index in the second-lowest word of xmm1.
VEX.128.66.0F38.WIG 41 /rVPHMINPOSUW xmm1, xmm2/m128RMValidValidFind the minimum unsigned word in xmm2/m128 and place its value in the low word of xmm1 and its index in the second-lowest word of xmm1.

Operand encoding

Each mode is a value of the Op/En column above. It says which field of the encoded instruction carries each operand, in the order they are written, and whether the instruction reads it, writes it or both.

RM

  1. modrm.reg escrituraModRM byte, reg field (bits 5-3)
  2. modrm.rm lecturaModRM byte, r/m field (bits 2-0); with the SIB byte and the displacement when the mod field asks for them

Measured cost

Loading measurements from arch-data...

Description

Determine the minimum unsigned word value in the source operand (second operand) and place the unsigned word in the low word (bits 0-15) of the destination operand (first operand). The word index of the minimum value is stored in bits 16-18 of the destination operand. The remaining upper bits of the destination are set to zero.

128-bit Legacy SSE version: Bits (MAXVL-1:128) of the corresponding XMM destination register remain unchanged.

VEX.128 encoded version: Bits (MAXVL-1:128) of the destination XMM register are zeroed. VEX.vvvv is reserved and must be 1111b, VEX.L must be 0, otherwise the instruction will #UD.

Operation

PHMINPOSUW (128-bit Legacy SSE Version)
INDEX := 0;
MIN := SRC[15:0]
IF (SRC[31:16] < MIN)

    THEN INDEX := 1; MIN := SRC[31:16]; FI;
IF (SRC[47:32] < MIN)

    THEN INDEX := 2; MIN := SRC[47:32]; FI;
* Repeat operation for words 3 through 6
IF (SRC[127:112] < MIN)

    THEN INDEX := 7; MIN := SRC[127:112]; FI;
DEST[15:0] := MIN;
DEST[18:16] := INDEX;
DEST[127:19] := 0000000000000000000000000000H;

VPHMINPOSUW (VEX.128 Encoded Version)
INDEX := 0
MIN := SRC[15:0]
IF (SRC[31:16] < MIN) THEN INDEX := 1; MIN := SRC[31:16]
IF (SRC[47:32] < MIN) THEN INDEX := 2; MIN := SRC[47:32]
* Repeat operation for words 3 through 6
IF (SRC[127:112] < MIN) THEN INDEX := 7; MIN := SRC[127:112]
DEST[15:0] := MIN
DEST[18:16] := INDEX
DEST[127:19] := 0000000000000000000000000000H
DEST[MAXVL-1:128] := 0

Intel C/C++ compiler intrinsics

PHMINPOSUW __m128i _mm_minpos_epu16( __m128i packed_words);

Flags affected

None.

SIMD Floating-Point Exceptions

None.

Other Exceptions

See Table 2-21, "Type 4 Class Exception Conditions," additionally:

#UD               If VEX.L = 1.
                  If VEX.vvvv  1111B.

Sources