| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 |
| 24 | ENTRY(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 | |
| 49 | L_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 | |
| 65 | L_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 | |
| 80 | L_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 |