| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /*---------------------------------------------------------------------------+ |
| 2 | | round_Xsig.S | |
| 3 | | | |
| 4 | | Copyright (C) 1992,1993,1994,1995 | |
| 5 | | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, | |
| 6 | | Australia. E-mail billm@jacobi.maths.monash.edu.au | |
| 7 | | | |
| 8 | | Normalize and round a 12 byte quantity. | |
| 9 | | Call from C as: | |
| 10 | | int round_Xsig(Xsig *n) | |
| 11 | | | |
| 12 | | Normalize a 12 byte quantity. | |
| 13 | | Call from C as: | |
| 14 | | int norm_Xsig(Xsig *n) | |
| 15 | | | |
| 16 | | Each function returns the size of the shift (nr of bits). | |
| 17 | | | |
| 18 | +---------------------------------------------------------------------------*/ |
| 19 | .file "round_Xsig.S" |
| 20 | |
| 21 | #include "fpu_emu.h" |
| 22 | |
| 23 | |
| 24 | .text |
| 25 | ENTRY(round_Xsig) |
| 26 | pushl %ebp |
| 27 | movl %esp,%ebp |
| 28 | pushl %ebx /* Reserve some space */ |
| 29 | pushl %ebx |
| 30 | pushl %esi |
| 31 | |
| 32 | movl PARAM1,%esi |
| 33 | |
| 34 | movl 8(%esi),%edx |
| 35 | movl 4(%esi),%ebx |
| 36 | movl (%esi),%eax |
| 37 | |
| 38 | movl $0,-4(%ebp) |
| 39 | |
| 40 | orl %edx,%edx /* ms bits */ |
| 41 | js L_round /* Already normalized */ |
| 42 | jnz L_shift_1 /* Shift left 1 - 31 bits */ |
| 43 | |
| 44 | movl %ebx,%edx |
| 45 | movl %eax,%ebx |
| 46 | xorl %eax,%eax |
| 47 | movl $-32,-4(%ebp) |
| 48 | |
| 49 | /* We need to shift left by 1 - 31 bits */ |
| 50 | L_shift_1: |
| 51 | bsrl %edx,%ecx /* get the required shift in %ecx */ |
| 52 | subl $31,%ecx |
| 53 | negl %ecx |
| 54 | subl %ecx,-4(%ebp) |
| 55 | shld %cl,%ebx,%edx |
| 56 | shld %cl,%eax,%ebx |
| 57 | shl %cl,%eax |
| 58 | |
| 59 | L_round: |
| 60 | testl $0x80000000,%eax |
| 61 | jz L_exit |
| 62 | |
| 63 | addl $1,%ebx |
| 64 | adcl $0,%edx |
| 65 | jnz L_exit |
| 66 | |
| 67 | movl $0x80000000,%edx |
| 68 | incl -4(%ebp) |
| 69 | |
| 70 | L_exit: |
| 71 | movl %edx,8(%esi) |
| 72 | movl %ebx,4(%esi) |
| 73 | movl %eax,(%esi) |
| 74 | |
| 75 | movl -4(%ebp),%eax |
| 76 | |
| 77 | popl %esi |
| 78 | popl %ebx |
| 79 | leave |
| 80 | ret |
| 81 | |
| 82 | |
| 83 | |
| 84 | |
| 85 | ENTRY(norm_Xsig) |
| 86 | pushl %ebp |
| 87 | movl %esp,%ebp |
| 88 | pushl %ebx /* Reserve some space */ |
| 89 | pushl %ebx |
| 90 | pushl %esi |
| 91 | |
| 92 | movl PARAM1,%esi |
| 93 | |
| 94 | movl 8(%esi),%edx |
| 95 | movl 4(%esi),%ebx |
| 96 | movl (%esi),%eax |
| 97 | |
| 98 | movl $0,-4(%ebp) |
| 99 | |
| 100 | orl %edx,%edx /* ms bits */ |
| 101 | js L_n_exit /* Already normalized */ |
| 102 | jnz L_n_shift_1 /* Shift left 1 - 31 bits */ |
| 103 | |
| 104 | movl %ebx,%edx |
| 105 | movl %eax,%ebx |
| 106 | xorl %eax,%eax |
| 107 | movl $-32,-4(%ebp) |
| 108 | |
| 109 | orl %edx,%edx /* ms bits */ |
| 110 | js L_n_exit /* Normalized now */ |
| 111 | jnz L_n_shift_1 /* Shift left 1 - 31 bits */ |
| 112 | |
| 113 | movl %ebx,%edx |
| 114 | movl %eax,%ebx |
| 115 | xorl %eax,%eax |
| 116 | addl $-32,-4(%ebp) |
| 117 | jmp L_n_exit /* Might not be normalized, |
| 118 | but shift no more. */ |
| 119 | |
| 120 | /* We need to shift left by 1 - 31 bits */ |
| 121 | L_n_shift_1: |
| 122 | bsrl %edx,%ecx /* get the required shift in %ecx */ |
| 123 | subl $31,%ecx |
| 124 | negl %ecx |
| 125 | subl %ecx,-4(%ebp) |
| 126 | shld %cl,%ebx,%edx |
| 127 | shld %cl,%eax,%ebx |
| 128 | shl %cl,%eax |
| 129 | |
| 130 | L_n_exit: |
| 131 | movl %edx,8(%esi) |
| 132 | movl %ebx,4(%esi) |
| 133 | movl %eax,(%esi) |
| 134 | |
| 135 | movl -4(%ebp),%eax |
| 136 | |
| 137 | popl %esi |
| 138 | popl %ebx |
| 139 | leave |
| 140 | ret |
| 141 | |