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|
.file "shr_Xsig.S"
/*---------------------------------------------------------------------------+
| shr_Xsig.S |
| |
| 12 byte right shift function |
| |
| Copyright (C) 1992,1994,1995 |
| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
| Australia. E-mail billm@jacobi.maths.monash.edu.au |
| |
| Call from C as: |
| void shr_Xsig(Xsig *arg, unsigned nr) |
| |
| Extended shift right function. |
| Fastest for small shifts. |
| Shifts the 12 byte quantity pointed to by the first arg (arg) |
| right by the number of bits specified by the second arg (nr). |
| |
+---------------------------------------------------------------------------*/
#include "fpu_emu.h"
.text
ENTRY(shr_Xsig)
push %ebp
movl %esp,%ebp
pushl %esi
movl PARAM2,%ecx
movl PARAM1,%esi
cmpl $32,%ecx /* shrd only works for 0..31 bits */
jnc L_more_than_31
/* less than 32 bits */
pushl %ebx
movl (%esi),%eax /* lsl */
movl 4(%esi),%ebx /* midl */
movl 8(%esi),%edx /* msl */
shrd %cl,%ebx,%eax
shrd %cl,%edx,%ebx
shr %cl,%edx
movl %eax,(%esi)
movl %ebx,4(%esi)
movl %edx,8(%esi)
popl %ebx
popl %esi
leave
ret
L_more_than_31:
cmpl $64,%ecx
jnc L_more_than_63
subb $32,%cl
movl 4(%esi),%eax /* midl */
movl 8(%esi),%edx /* msl */
shrd %cl,%edx,%eax
shr %cl,%edx
movl %eax,(%esi)
movl %edx,4(%esi)
movl $0,8(%esi)
popl %esi
leave
ret
L_more_than_63:
cmpl $96,%ecx
jnc L_more_than_95
subb $64,%cl
movl 8(%esi),%eax /* msl */
shr %cl,%eax
xorl %edx,%edx
movl %eax,(%esi)
movl %edx,4(%esi)
movl %edx,8(%esi)
popl %esi
leave
ret
L_more_than_95:
xorl %eax,%eax
movl %eax,(%esi)
movl %eax,4(%esi)
movl %eax,8(%esi)
popl %esi
leave
ret
|
