vgetmantpd
Get Mantissa Packed Double-Precision
Extracts mantissas from doubles.
Pseudocode Operation
for i = 0 to 7:
src_val = zmm2/m512[i*64 + 63 : i*64]
mantissa_mode = imm8[1:0]
round_mode = imm8[3:2]
suppress_exceptions = imm8[4]
mantissa = ExtractMantissa(src_val, mantissa_mode)
rounded_mantissa = RoundMantissa(mantissa, round_mode)
result[i*64 + 63 : i*64] = rounded_mantissa
if (suppress_exceptions == 0 and exception_condition):
set_FP_exception_flags()
if k1_mask[i] == 1:
zmm1[i*64 + 63 : i*64] = result[i*64 + 63 : i*64]
else if {z} == 1:
zmm1[i*64 + 63 : i*64] = 0Example
Encoding
Operands
-
dest
512-bit ZMM AVX-512 register -
src1
512-bit ZMM AVX-512 register or Memory operand -
src2
8-bit signed immediate
Related
More in AVX-512F
Reference
Instruction Forms
| Opcode | Instruction | Op/En | 64/32-bit Mode | CPUID | Description |
|---|---|---|---|---|---|
| EVEX.128.66.0F3A.W1 26 /r ib | VGETMANTPD xmm1 {k1}{z}, xmm2/m128/m64bcst, imm8 | A | V/V | (AVX512VL AND AVX512F) OR AVX10.1 | Get Normalized Mantissa from float64 vector xmm2/m128/m64bcst and store the result in xmm1, using imm8 for sign control and mantissa interval normalization, under writemask. |
| EVEX.256.66.0F3A.W1 26 /r ib | VGETMANTPD ymm1 {k1}{z}, ymm2/m256/m64bcst, imm8 | A | V/V | (AVX512VL AND AVX512F) OR AVX10.1 | Get Normalized Mantissa from float64 vector ymm2/m256/m64bcst and store the result in ymm1, using imm8 for sign control and mantissa interval normalization, under writemask. |
| EVEX.512.66.0F3A.W1 26 /r ib | VGETMANTPD zmm1 {k1}{z}, zmm2/m512/m64bcst{sae}, imm8 | A | V/V | AVX512F OR AVX10.1 | Get Normalized Mantissa from float64 vector zmm2/m512/m64bcst and store the result in zmm1, using imm8 for sign control and mantissa interval normalization, under writemask. |
Instruction Operand Encoding
| Op/En | Tuple Type | Operand 1 | Operand 2 | Operand 3 | Operand 4 |
|---|---|---|---|---|---|
| A | Full | ModRM:reg (w) | ModRM:r/m (r) | imm8 | N/A |
Description
Convert double precision floating values in the source operand (the second operand) to double precision floatingpoint values with the mantissa normalization and sign control specified by the imm8 byte, see Figure 5-15. The converted results are written to the destination operand (the first operand) using writemask k1. The normalized mantissa is specified by interv (imm8[1:0]) and the sign control (sc) is specified by bits 3:2 of the immediate byte. The destination operand is a ZMM/YMM/XMM register updated under the writemask. The source operand can be a ZMM/YMM/XMM register, a 512/256/128-bit memory location, or a 512/256/128-bit vector broadcasted from a 64bit memory location.
7 6 5 4 3 2 1 0 imm8 Must Be Zero Sign Control (SC) Normaiization Interval
Imm8[1:0] = 00b : Interval is [ 1, 2)
Imm8[3:2] = 00b : sign(SRC) Imm8[1:0] = 01b : Interval is [1/2, 2) Imm8[3:2] = 01b : 0 Imm8[1:0] = 10b : Interval is [ 1/2, 1) Imm8[3] = 1b : qNan_Indefinite if sign(SRC) != 0, regardless of imm8[2]. Imm8[1:0] = 11b : Interval is [3/4, 3/2)
For each input double precision floating-point value x, The conversion operation is:
GetMant(x) = ±2k|x.significand| where:
1 <= |x.significand| < 2
Unbiased exponent k can be either 0 or -1, depending on the interval range defined by interv, the range of the significand and whether the exponent of the source is even or odd. The sign of the final result is determined by sc and the source sign. The encoded value of imm8[1:0] and sign control are shown in Figure 5-15. Each converted double precision floating-point result is encoded according to the sign control, the unbiased exponent k (adding bias) and a mantissa normalized to the range specified by interv. The GetMant() function follows Table 5-16 when dealing with floating-point special numbers. This instruction is writemasked, so only those elements with the corresponding bit set in vector mask register k1 are computed and stored into the destination. Elements in zmm1 with the corresponding bit clear in k1 retain their previous values. Note: EVEX.vvvv is reserved and must be 1111b; otherwise instructions will #UD.
Table 5-16. GetMant() Special Float Values Behavior
Input Result Exceptions / Comments NaN QNaN(SRC) Ignore interv
If (SRC = SNaN) then #IE
+∞ 1.0 Ignore interv +0 1.0 Ignore interv -0 IF (SC[0]) THEN +1.0 Ignore interv
ELSE -1.0
-∞ IF (SC[1]) THEN {QNaN_Indefinite} Ignore interv
ELSE { If (SC[1]) then #IEIF (SC[0]) THEN +1.0
ELSE -1.0 negative SC[1] ? QNaN_Indefinite : Getmant(SRC)1 If (SC[1]) then #IE
Operation
def getmant_fp64(src, sign_control, normalization_interval):
bias := 1023
dst.sign := sign_control[0] ? 0 : src.sign
signed_one := sign_control[0] ? +1.0 : -1.0
dst.exp := src.exp
dst.fraction := src.fraction
zero := (dst.exp = 0) and ((dst.fraction = 0) or (MXCSR.DAZ=1))
denormal := (dst.exp = 0) and (dst.fraction != 0) and (MXCSR.DAZ=0)
infinity := (dst.exp = 0x7FF) and (dst.fraction = 0)
nan := (dst.exp = 0x7FF) and (dst.fraction != 0)
src_signaling := src.fraction[51]
snan := nan and (src_signaling = 0)
positive := (src.sign = 0)
negative := (src.sign = 1)
if nan:
if snan:
MXCSR.IE := 1
return qnan(src)
if positive and (zero or infinity):
return 1.0
if negative:
if zero:
return signed_one
if infinity:
if sign_control[1]:
MXCSR.IE := 1
return QNaN_Indefinite
return signed_one
if sign_control[1]:
MXCSR.IE := 1
return QNaN_Indefinite
if denormal:
jbit := 0
dst.exp := bias
while jbit = 0:
jbit := dst.fraction[51]
dst.fraction := dst.fraction << 1
dst.exp : = dst.exp - 1
MXCSR.DE := 1
unbiased_exp := dst.exp - bias
odd_exp := unbiased_exp[0]
signaling_bit := dst.fraction[51]
if normalization_interval = 0b00:
dst.exp := bias
else if normalization_interval = 0b01:
dst.exp := odd_exp ? bias-1 : bias
else if normalization_interval = 0b10:
dst.exp := bias-1
else if normalization_interval = 0b11:
dst.exp := signaling_bit ? bias-1 : bias
return dst
VGETMANTPD (EVEX Encoded Versions)
VGETMANTPD dest{k1}, src, imm8
VL = 128, 256, or 512
KL := VL / 64
sign_control := imm8[3:2]
normalization_interval := imm8[1:0]
FOR i := 0 to KL-1:
IF k1[i] or *no writemask*:
IF SRC is memory and (EVEX.b = 1):
tsrc := src.double[0]
ELSE:
tsrc := src.double[i]
DEST.double[i] := getmant_fp64(tsrc, sign_control, normalization_interval)
ELSE IF *zeroing*:
DEST.double[i] := 0
//else DEST.double[i] remains unchanged
DEST[MAX_VL-1:VL] := 0Intel C/C++ Compiler Intrinsic Equivalent
VGETMANTPD __m512d _mm512_getmant_pd( __m512d a, enum intv, enum sgn); VGETMANTPD __m512d _mm512_mask_getmant_pd(__m512d s, __mmask8 k, __m512d a, enum intv, enum sgn); VGETMANTPD __m512d _mm512_maskz_getmant_pd( __mmask8 k, __m512d a, enum intv, enum sgn); VGETMANTPD __m512d _mm512_getmant_round_pd( __m512d a, enum intv, enum sgn, int r); VGETMANTPD __m512d _mm512_mask_getmant_round_pd(__m512d s, __mmask8 k, __m512d a, enum intv, enum sgn, int r); VGETMANTPD __m512d _mm512_maskz_getmant_round_pd( __mmask8 k, __m512d a, enum intv, enum sgn, int r); VGETMANTPD __m256d _mm256_getmant_pd( __m256d a, enum intv, enum sgn); VGETMANTPD __m256d _mm256_mask_getmant_pd(__m256d s, __mmask8 k, __m256d a, enum intv, enum sgn); VGETMANTPD __m256d _mm256_maskz_getmant_pd( __mmask8 k, __m256d a, enum intv, enum sgn); VGETMANTPD __m128d _mm_getmant_pd( __m128d a, enum intv, enum sgn); VGETMANTPD __m128d _mm_mask_getmant_pd(__m128d s, __mmask8 k, __m128d a, enum intv, enum sgn); VGETMANTPD __m128d _mm_maskz_getmant_pd( __mmask8 k, __m128d a, enum intv, enum sgn);