1 .file "shr_Xsig.S" 2/*---------------------------------------------------------------------------+ 3 | shr_Xsig.S | 4 | | 5 | 12 byte right shift function | 6 | | 7 | Copyright (C) 1992,1994,1995 | 8 | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, | 9 | Australia. E-mail billm@jacobi.maths.monash.edu.au | 10 | | 11 | Call from C as: | 12 | void shr_Xsig(Xsig *arg, unsigned nr) | 13 | | 14 | Extended shift right function. | 15 | Fastest for small shifts. | 16 | Shifts the 12 byte quantity pointed to by the first arg (arg) | 17 | right by the number of bits specified by the second arg (nr). | 18 | | 19 +---------------------------------------------------------------------------*/ 20 21#include "fpu_emu.h" 22 23.text 24ENTRY(shr_Xsig) 25 push %ebp 26 movl %esp,%ebp 27 pushl %esi 28 movl PARAM2,%ecx 29 movl PARAM1,%esi 30 cmpl $32,%ecx /* shrd only works for 0..31 bits */ 31 jnc L_more_than_31 32 33/* less than 32 bits */ 34 pushl %ebx 35 movl (%esi),%eax /* lsl */ 36 movl 4(%esi),%ebx /* midl */ 37 movl 8(%esi),%edx /* msl */ 38 shrd %cl,%ebx,%eax 39 shrd %cl,%edx,%ebx 40 shr %cl,%edx 41 movl %eax,(%esi) 42 movl %ebx,4(%esi) 43 movl %edx,8(%esi) 44 popl %ebx 45 popl %esi 46 leave 47 ret 48 49L_more_than_31: 50 cmpl $64,%ecx 51 jnc L_more_than_63 52 53 subb $32,%cl 54 movl 4(%esi),%eax /* midl */ 55 movl 8(%esi),%edx /* msl */ 56 shrd %cl,%edx,%eax 57 shr %cl,%edx 58 movl %eax,(%esi) 59 movl %edx,4(%esi) 60 movl $0,8(%esi) 61 popl %esi 62 leave 63 ret 64 65L_more_than_63: 66 cmpl $96,%ecx 67 jnc L_more_than_95 68 69 subb $64,%cl 70 movl 8(%esi),%eax /* msl */ 71 shr %cl,%eax 72 xorl %edx,%edx 73 movl %eax,(%esi) 74 movl %edx,4(%esi) 75 movl %edx,8(%esi) 76 popl %esi 77 leave 78 ret 79 80L_more_than_95: 81 xorl %eax,%eax 82 movl %eax,(%esi) 83 movl %eax,4(%esi) 84 movl %eax,8(%esi) 85 popl %esi 86 leave 87 ret 88