x86 architecture
datatypes




 
integer datatype formats
 
 
signed byte
7 6...0
S integer
signed word
15 14...0
S integer
signed dword
31 30...0
S integer
signed qword
63 63...0
S integer
 
unsigned byte
7...0
integer
unsigned word
15...0
integer
unsigned dword
31...0
integer
unsigned qword
63...0
integer
 
BCD
7...4 3...0
res. BCD
packed BCD
7...4 3...0
BCD BCD
 
 
FP datatype formats
 
 
half real
15 14...10 9...0
S exp. fraction
single real
31 30...23 22...0
S exp. fraction
double real
63 62...52 51...0
S exp. fraction
extended real
79 78...64 63 62...0
S exp. I fraction
 
word integer
15 14...0
S integer
short integer
31 30...0
S integer
long integer
63 62...0
S integer
 
packed BCD
79 78...72 71...0
S res. D17 D16 D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
 
 
MMX datatype formats
 
 
packed byte
63...
...56
55...
...48
47...
...40
39...
...32
31...
...24
23...
...16
15...
...8
7...
...0
byte byte byte byte byte byte byte byte
packed word
63...48 47...32 31...16 15...0
word word word word
packed dword
63...32 31...0
dword dword
qword
63...0
qword
packed byte
127...
...120
119...
...112
111...
...104
103...
...96
95...
...88
87...
...80
79...
...72
71...
...64
63...
...56
55...
...48
47...
...40
39...
...32
31...
...24
23...
...16
15...
...8
7...
...0
byte byte byte byte byte byte byte byte byte byte byte byte byte byte byte byte
packed word
127...112 111...96 95...80 79...64 63...48 47...32 31...16 15...0
word word word word word word word word
packed dword
127...96 95...64 63...32 31...0
dword dword dword dword
packed qword
127...64 63...0
qword qword
 
 
SSE datatype formats
 
 
scalar single FP
127...96 95...64 63...32 31...0
reserved reserved reserved single FP
packed single FP
127...96 95...64 63...32 31...0
single FP single FP single FP single FP
 
 
SSE2 datatype formats
 
 
scalar double FP
127...64 63...0
reserved double FP
packed double FP
127...64 63...0
double FP double FP
 
 
F16C datatype format
 
 
packed half FP
63...48 47...32 31...16 15...0
half FP half FP half FP half FP
packed half FP
127...112 111...96 95...80 79...64 63...48 47...32 31...16 15...0
half FP half FP half FP half FP half FP half FP half FP half FP
 
 
AVX datatype formats
 
 
packed byte
2
4
8
2
4
0
2
3
2
2
2
4
2
1
6
2
0
8
2
0
0
1
9
2
1
8
4
1
7
6
1
6
8
1
6
0
1
5
2
1
4
4
1
3
6
1
2
8
1
2
0
1
1
2
1
0
4
9
6
8
8
8
0
7
2
6
4
5
6
4
8
4
0
3
2
2
4
1
6
8 0
b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b.
packed word
255...
...240
239...
...224
223...
...208
207...
...192
191...
...176
175...
...160
159...
...144
143...
...128
127...
...112
111...
...96
95...
...80
79...
...64
63...
...48
47...
...32
31...
...16
15...
...0
word word word word word word word word word word word word word word word word
packed dword
255...224 223...192 191...160 159...128 127...96 95...64 63...32 31...0
dword dword dword dword dword dword dword dword
packed qword
255...192 191...128 127...64 63...0
qword qword qword qword
scalar single FP
255...224 223...192 191...160 159...128 127...96 95...64 63...32 31...0
reserved reserved reserved reserved reserved reserved reserved single FP
scalar double FP
255...192 191...128 127...64 63...0
reserved reserved reserved double FP
packed single FP
255...224 223...192 191...160 159...128 127...96 95...64 63...32 31...0
single FP single FP single FP single FP single FP single FP single FP single FP
packed double FP
255...192 191...128 127...64 63...0
double FP double FP double FP double FP
 
 
MVEX datatype formats
 
 
packed dword
512...
...480
479...
...448
447...
...416
415...
...384
383...
...352
351...
...320
319...
...288
287...
...256
255...
...224
223...
...192
191...
...160
159...
...128
127...
...96
95...
...64
63...
...32
31...
...0
d d d d d d d d d d d d d d d d
packed qword
512...448 447...384 383...320 319...256 255...192 191...128 127...64 63...0
q q q q q q q q
scalar single FP
512...
...480
479...
...448
447...
...416
415...
...384
383...
...352
351...
...320
319...
...288
287...
...256
255...
...224
223...
...192
191...
...160
159...
...128
127...
...96
95...
...64
63...
...32
31...
...0
r. r. r. r. r. r. r. r. r. r. r. r. r. r. r. sp
scalar double FP
512...448 447...384 383...320 319...256 255...192 191...128 127...64 63...0
r. r. r. r. r. r. r. dp
packed single FP
512...
...480
479...
...448
447...
...416
415...
...384
383...
...352
351...
...320
319...
...288
287...
...256
255...
...224
223...
...192
191...
...160
159...
...128
127...
...96
95...
...64
63...
...32
31...
...0
sp sp sp sp sp sp sp sp sp sp sp sp sp sp sp sp
packed double FP
512...448 447...384 383...320 319...256 255...192 191...128 127...64 63...0
dp dp dp dp dp dp dp dp
 
 
EVEX datatype formats
 
 
packed byte
5
0
4
4
9
6
4
8
8
4
8
0
4
7
2
4
6
4
4
5
6
4
4
8
4
4
0
4
3
2
4
2
4
4
1
6
4
0
8
4
0
0
3
9
2
3
8
4
3
7
6
3
6
8
3
6
0
3
5
2
3
4
4
3
3
6
3
2
8
3
2
0
3
1
2
3
0
4
2
9
6
2
8
8
2
8
0
2
7
2
2
6
4
2
5
6
2
4
8
2
4
0
2
3
2
2
2
4
2
1
6
2
0
8
2
0
0
1
9
2
1
8
4
1
7
6
1
6
8
1
6
0
1
5
2
1
4
4
1
3
6
1
2
8
1
2
0
1
1
2
1
0
4
9
6
8
8
8
0
7
2
6
4
5
6
4
8
4
0
3
2
2
4
1
6
8 0
b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b. b.
packed word
4
9
6
4
8
0
4
6
4
4
4
8
4
3
2
4
1
6
4
0
0
3
8
4
3
6
8
3
5
2
3
3
6
3
2
0
3
0
4
2
8
8
2
7
2
2
5
6
2
4
0
2
2
4
2
0
8
1
9
2
1
7
6
1
6
0
1
4
4
1
2
8
1
1
2
9
6
8
0
6
4
4
8
3
2
1
6
0
w. w. w. w. w. w. w. w. w. w. w. w. w. w. w. w. w. w. w. w. w. w. w. w. w. w. w. w. w. w. w. w.
packed dword
512...
...480
479...
...448
447...
...416
415...
...384
383...
...352
351...
...320
319...
...288
287...
...256
255...
...224
223...
...192
191...
...160
159...
...128
127...
...96
95...
...64
63...
...32
31...
...0
d d d d d d d d d d d d d d d d
packed qword
512...448 447...384 383...320 319...256 255...192 191...128 127...64 63...0
q q q q q q q q
scalar single FP
512...
...480
479...
...448
447...
...416
415...
...384
383...
...352
351...
...320
319...
...288
287...
...256
255...
...224
223...
...192
191...
...160
159...
...128
127...
...96
95...
...64
63...
...32
31...
...0
r. r. r. r. r. r. r. r. r. r. r. r. r. r. r. sp
scalar double FP
512...448 447...384 383...320 319...256 255...192 191...128 127...64 63...0
r. r. r. r. r. r. r. dp
packed single FP
512...
...480
479...
...448
447...
...416
415...
...384
383...
...352
351...
...320
319...
...288
287...
...256
255...
...224
223...
...192
191...
...160
159...
...128
127...
...96
95...
...64
63...
...32
31...
...0
sp sp sp sp sp sp sp sp sp sp sp sp sp sp sp sp
packed double FP
512...448 447...384 383...320 319...256 255...192 191...128 127...64 63...0
dp dp dp dp dp dp dp dp



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