PSIGNB/PSIGNW/PSIGND — Packed SIGN

Notes: 1. See note in Section 2.4, “Instruction Exception Specification” in the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 2A and Section 22.25.3, “Exception Conditions of Legacy SIMD Instructions Operating on MMX Registers” in the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 3A.

Instruction Operand Encoding

Description

(V)PSIGNB/(V)PSIGNW/(V)PSIGND negates each data element of the destination operand (the first operand) if the signed integer value of the corresponding data element in the source operand (the second operand) is less than zero. If the signed integer value of a data element in the source operand is positive, the corresponding data element in the destination operand is unchanged. If a data element in the source operand is zero, the corresponding data element in the destination operand is set to zero.

(V)PSIGNB operates on signed bytes. (V)PSIGNW operates on 16-bit signed words. (V)PSIGND operates on signed 32-bit integers. When the source operand is a 128bit memory operand, the operand must be aligned on a 16-byte boundary or a general-protection exception (#GP) will be generated.

Legacy SSE instructions: Both operands can be MMX registers. In 64-bit mode, use the REX prefix to access additional registers. 128-bit Legacy SSE version: The first source and destination operands are XMM registers. The second source operand is an XMM register or a 128-bit memory location. Bits (VLMAX-1:128) of the corresponding YMM destination register remain unchanged. VEX.128 encoded version: The first source and destination operands are XMM registers. The second source operand is an XMM register or a 128-bit memory location. Bits (VLMAX-1:128) of the destination YMM register are zeroed. VEX.L must be 0, otherwise instructions will #UD. VEX.256 encoded version: The first source and destination operands are YMM registers. The second source operand is an YMM register or a 256-bit memory location.

Operation

PSIGNB (with 64 bit operands)
  IF (SRC[7:0] < 0 )
     DEST[7:0] ← Neg(DEST[7:0])
  ELSEIF (SRC[7:0] = 0 )
     DEST[7:0] ← 0
  ELSEIF (SRC[7:0] > 0 )
     DEST[7:0] ← DEST[7:0]
  Repeat operation for 2nd through 7th bytes
  IF (SRC[63:56] < 0 )
     DEST[63:56] ← Neg(DEST[63:56])
  ELSEIF (SRC[63:56] = 0 )
     DEST[63:56] ← 0
  ELSEIF (SRC[63:56] > 0 )
     DEST[63:56] ← DEST[63:56]
PSIGNB (with 128 bit operands)
  IF (SRC[7:0] < 0 )
     DEST[7:0] ← Neg(DEST[7:0])
  ELSEIF (SRC[7:0] = 0 )
     DEST[7:0] ← 0
  ELSEIF (SRC[7:0] > 0 )
     DEST[7:0] ← DEST[7:0]
  Repeat operation for 2nd through 15th bytes
  IF (SRC[127:120] < 0 )
     DEST[127:120] ← Neg(DEST[127:120])
  ELSEIF (SRC[127:120] = 0 )
     DEST[127:120] ← 0
  ELSEIF (SRC[127:120] > 0 )
     DEST[127:120] ← DEST[127:120]
VPSIGNB (VEX.128 encoded version)
DEST[127:0] ←BYTE_SIGN(SRC1, SRC2)
DEST[VLMAX-1:128] ← 0
VPSIGNB (VEX.256 encoded version)
DEST[255:0] ←BYTE_SIGN_256b(SRC1, SRC2)
PSIGNW (with 64 bit operands)
  IF (SRC[15:0] < 0 )
     DEST[15:0] ← Neg(DEST[15:0])
  ELSEIF (SRC[15:0] = 0 )
     DEST[15:0] ← 0
  ELSEIF (SRC[15:0] > 0 )
     DEST[15:0] ← DEST[15:0]
Repeat operation for 2nd through 3rd words
  IF (SRC[63:48] < 0 )
     DEST[63:48] ← Neg(DEST[63:48])
  ELSEIF (SRC[63:48] = 0 )
     DEST[63:48] ← 0
  ELSEIF (SRC[63:48] > 0 )
     DEST[63:48] ← DEST[63:48]
PSIGNW (with 128 bit operands)
  IF (SRC[15:0] < 0 )
     DEST[15:0] ← Neg(DEST[15:0])
  ELSEIF (SRC[15:0] = 0 )
     DEST[15:0] ← 0
  ELSEIF (SRC[15:0] > 0 )
     DEST[15:0] ← DEST[15:0]
  Repeat operation for 2nd through 7th words
  IF (SRC[127:112] < 0 )
     DEST[127:112] ← Neg(DEST[127:112])
  ELSEIF (SRC[127:112] = 0 )
     DEST[127:112] ← 0
  ELSEIF (SRC[127:112] > 0 )
     DEST[127:112] ← DEST[127:112]
VPSIGNW (VEX.128 encoded version)
DEST[127:0] ←WORD_SIGN(SRC1, SRC2)
DEST[VLMAX-1:128] ← 0
VPSIGNW (VEX.256 encoded version)
DEST[255:0] ←WORD_SIGN(SRC1, SRC2)
PSIGND (with 64 bit operands)
  IF (SRC[31:0] < 0 )
     DEST[31:0] ← Neg(DEST[31:0])
  ELSEIF (SRC[31:0] = 0 )
     DEST[31:0] ← 0
  ELSEIF (SRC[31:0] > 0 )
     DEST[31:0] ← DEST[31:0]
  IF (SRC[63:32] < 0 )
     DEST[63:32] ← Neg(DEST[63:32])
  ELSEIF (SRC[63:32] = 0 )
     DEST[63:32] ← 0
  ELSEIF (SRC[63:32] > 0 )
     DEST[63:32] ← DEST[63:32]
PSIGND (with 128 bit operands)
  IF (SRC[31:0] < 0 )
     DEST[31:0] ← Neg(DEST[31:0])
  ELSEIF (SRC[31:0] = 0 )
     DEST[31:0] ← 0
  ELSEIF (SRC[31:0] > 0 )
     DEST[31:0] ← DEST[31:0]
  Repeat operation for 2nd through 3rd double words
  IF (SRC[127:96] < 0 )
     DEST[127:96] ← Neg(DEST[127:96])
  ELSEIF (SRC[127:96] = 0 )
     DEST[127:96] ← 0
  ELSEIF (SRC[127:96] > 0 )
     DEST[127:96] ← DEST[127:96]
VPSIGND (VEX.128 encoded version)
DEST[127:0] ←DWORD_SIGN(SRC1, SRC2)
DEST[VLMAX-1:128] ← 0
VPSIGND (VEX.256 encoded version)
DEST[255:0] ←DWORD_SIGN(SRC1, SRC2)

Intel C/C++ Compiler Intrinsic Equivalent

SIMD Floating-Point Exceptions

None.

Other Exceptions

See Exceptions Type 4; additionally