Assembly code snippets
Details
| Title | Hexadecimal String to DWORD (MMX) |
|---|---|
| Author | bitRAKE |
| Submitted by: | bitRAKE |
| Date added: | 2002-03-24 03:41:40 |
| Date modified: | 2002-03-24 03:41:40 |
Comments
Fastest conversion of a hexadecimal number to DWORD
Snippet
StrHex2bin PROC
_CONST SEGMENT
lpString db "89aBcDeF"
_CONST ENDS
movq mm0,QWORD PTR [lpString]
psubusb mm0,mxc(<30>) ; "0" = 0
movq mm1,mm0
pcmpgtb mm1,mxc(<09>) ; letter?
pand mm1,mxc(<07>)
psubusb mm0,mm1 ; fix letters
movq mm1,mm0 ; 0F0E0D0C0B0A0908
pand mm0,mxc(<0F00>) ; 0E000C000A000800
pand mm1,mxc(<000F>) ; 000F000D000B0009
psrlq mm0,8 ; 000E000C000A0008
packuswb mm1,mm1 ; 0F0D0B09
packuswb mm0,mm0 ; 0E0C0A08
psllq mm1,4 ; F0D0B090
por mm0,mm1 ; FEDCBA98
movd eax,mm0 ; FEDCBA98
bswap eax ; 89ABCDEF
ret
StrHex2bin ENDP
_CONST SEGMENT
lpString db "89aBcDeF"
_CONST ENDS
movq mm0,QWORD PTR [lpString]
psubusb mm0,mxc(<30>) ; "0" = 0
movq mm1,mm0
pcmpgtb mm1,mxc(<09>) ; letter?
pand mm1,mxc(<07>)
psubusb mm0,mm1 ; fix letters
movq mm1,mm0 ; 0F0E0D0C0B0A0908
pand mm0,mxc(<0F00>) ; 0E000C000A000800
pand mm1,mxc(<000F>) ; 000F000D000B0009
psrlq mm0,8 ; 000E000C000A0008
packuswb mm1,mm1 ; 0F0D0B09
packuswb mm0,mm0 ; 0E0C0A08
psllq mm1,4 ; F0D0B090
por mm0,mm1 ; FEDCBA98
movd eax,mm0 ; FEDCBA98
bswap eax ; 89ABCDEF
ret
StrHex2bin ENDP