x86doc › VDBPSADBW - Double Block Packed Sum-Absolute-Differences (SAD) on Unsigned Bytes

VDBPSADBW—Double Block Packed Sum-Absolute-Differences (SAD) on Unsigned Bytes

Opcode/Instruction	Op /En	64/32 bit Mode Support	CPUID Feature Flag	Description
EVEX.128.66.0F3A.W0 42 /r ib VDBPSADBW xmm1 {k1}{z}, xmm2, xmm3/m128, imm8	A	V/V	AVX512VL AVX512BW	Compute packed SAD word results of unsigned bytes in dword block from xmm2 with unsigned bytes of dword blocks transformed from xmm3/m128 using the shuffle controls in imm8. Results are written to xmm1 under the writemask k1.
EVEX.256.66.0F3A.W0 42 /r ib VDBPSADBW ymm1 {k1}{z}, ymm2, ymm3/m256, imm8	A	V/V	AVX512VL AVX512BW	Compute packed SAD word results of unsigned bytes in dword block from ymm2 with unsigned bytes of dword blocks transformed from ymm3/m256 using the shuffle controls in imm8. Results are written to ymm1 under the writemask k1.
EVEX.512.66.0F3A.W0 42 /r ib VDBPSADBW zmm1 {k1}{z}, zmm2, zmm3/m512, imm8	A	V/V	AVX512BW	Compute packed SAD word results of unsigned bytes in dword block from zmm2 with unsigned bytes of dword blocks transformed from zmm3/m512 using the shuffle controls in imm8. Results are written to zmm1 under the writemask k1.

Instruction Operand Encoding

Op/En	Tuple Type	Operand 1	Operand 2	Operand 3	Operand 4
A	Full Mem	ModRM:reg (w)	EVEX.vvvv (r)	ModRM:r/m (r)	imm8

Description

Compute packed SAD (sum of absolute differences) word results of unsigned bytes from two 32-bit dword elements. Packed SAD word results are calculated in multiples of qword superblocks, producing 4 SAD word results in each 64-bit superblock of the destination register.

Within each super block of packed word results, the SAD results from two 32-bit dword elements are calculated as follows:

The first source operand is a ZMM/YMM/XMM register. The second source operand is a ZMM/YMM/XMM register, or a 512/256/128-bit memory location. The destination operand is conditionally updated based on writemask k1 at 16-bit word granularity.

127+128*n DW3

95+128*n DW2 imm8 shuffle control

63+128*n DW1 0

31+128*n DW0 00B: DW0

10B: DW2 11B: DW3	128*n
127+128*n 128-bit Lane of Tmp1 24 32 _ abs + 47 63 _ abs	95+128*n Tmp1 sliding dword Src1 stationary dword 1 16 32 _ abs +	63+128*n 31 23 _ abs Tmp1 sliding dword Src1 stationary dword 1	31+128*n Tmp1 qword superblock 8 0 _ abs + 15 15 _ abs +	128*n Tmp1 sliding dword Src1 stationary dword 0 0 Tmp1 sliding dword 0 Src1 stationary dword 0 _ abs
63 Destination qword superblock	47	31	15	0

Figure 5-8. 64-bit Super Block of SAD Operation in VDBPSADBW

Operation

VDBPSADBW (EVEX Encoded Versions)

(KL, VL) = (8, 128), (16, 256), (32, 512)

Selection of quadruplets:

FOR I = 0 to VL step 128

TMP1[I+31:I] := select (SRC2[I+127: I], imm8[1:0])

TMP1[I+63: I+32] := select (SRC2[I+127: I], imm8[3:2])

TMP1[I+95: I+64] := select (SRC2[I+127: I], imm8[5:4])

TMP1[I+127: I+96] := select (SRC2[I+127: I], imm8[7:6])

END FOR

SAD of quadruplets:

FOR I =0 to VL step 64

TMP_DEST[I+15:I] := ABS(SRC1[I+7: I] - TMP1[I+7: I]) +

ABS(SRC1[I+15: I+8]- TMP1[I+15: I+8]) +

ABS(SRC1[I+23: I+16]- TMP1[I+23: I+16]) +

ABS(SRC1[I+31: I+24]- TMP1[I+31: I+24])

TMP_DEST[I+31: I+16] := ABS(SRC1[I+7: I] - TMP1[I+15: I+8]) +

ABS(SRC1[I+15: I+8]- TMP1[I+23: I+16]) +

ABS(SRC1[I+23: I+16]- TMP1[I+31: I+24]) +

ABS(SRC1[I+31: I+24]- TMP1[I+39: I+32])

TMP_DEST[I+47: I+32] := ABS(SRC1[I+39: I+32] - TMP1[I+23: I+16]) +

ABS(SRC1[I+47: I+40]- TMP1[I+31: I+24]) +

ABS(SRC1[I+55: I+48]- TMP1[I+39: I+32]) +

ABS(SRC1[I+63: I+56]- TMP1[I+47: I+40])

TMP_DEST[I+63: I+48] := ABS(SRC1[I+39: I+32] - TMP1[I+31: I+24]) +

ABS(SRC1[I+47: I+40] - TMP1[I+39: I+32]) +

ABS(SRC1[I+55: I+48] - TMP1[I+47: I+40]) +

ABS(SRC1[I+63: I+56] - TMP1[I+55: I+48])

ENDFOR

FOR j := 0 TO KL-1

i :=

j * 16

IF k1[j] OR *no writemask*

THEN DEST[i+15:i] := TMP_DEST[i+15:i]

ELSE

IF *merging-masking*

; merging-masking

THEN *DEST[i+15:i] remains unchanged*

ELSE

; zeroing-masking

DEST[i+15:i] := 0

FI

FI;

ENDFOR

DEST[MAXVL-1:VL] := 0

Intel C/C++ Compiler Intrinsic Equivalent

VDBPSADBW __m512i _mm512_dbsad_epu8(__m512i a, __m512i b int imm8);

VDBPSADBW __m512i _mm512_mask_dbsad_epu8(__m512i s, __mmask32 m, __m512i a, __m512i b int imm8);

VDBPSADBW __m512i _mm512_maskz_dbsad_epu8(__mmask32 m, __m512i a, __m512i b int imm8);

VDBPSADBW __m256i _mm256_dbsad_epu8(__m256i a, __m256i b int imm8);

VDBPSADBW __m256i _mm256_mask_dbsad_epu8(__m256i s, __mmask16 m, __m256i a, __m256i b int imm8);

VDBPSADBW __m256i _mm256_maskz_dbsad_epu8(__mmask16 m, __m256i a, __m256i b int imm8);

VDBPSADBW __m128i _mm_dbsad_epu8(__m128i a, __m128i b int imm8);

VDBPSADBW __m128i _mm_mask_dbsad_epu8(__m128i s, __mmask8 m, __m128i a, __m128i b int imm8);

VDBPSADBW __m128i _mm_maskz_dbsad_epu8(__mmask8 m, __m128i a, __m128i b int imm8);

SIMD Floating-Point Exceptions

None.

Other Exceptions

See Exceptions Type E4NF.nb in Table 2-50, “Type E4NF Class Exception Conditions.”