| /*---------------------------------------------------------------------------+ |
| | round_Xsig.S | |
| | | |
| | Copyright (C) 1992,1993,1994,1995 | |
| | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, | |
| | Australia. E-mail billm@jacobi.maths.monash.edu.au | |
| | | |
| | Normalize and round a 12 byte quantity. | |
| | Call from C as: | |
| | int round_Xsig(Xsig *n) | |
| | | |
| | Normalize a 12 byte quantity. | |
| | Call from C as: | |
| | int norm_Xsig(Xsig *n) | |
| | | |
| | Each function returns the size of the shift (nr of bits). | |
| | | |
| +---------------------------------------------------------------------------*/ |
| .file "round_Xsig.S" |
| |
| #include "fpu_emu.h" |
| |
| |
| .text |
| ENTRY(round_Xsig) |
| pushl %ebp |
| movl %esp,%ebp |
| pushl %ebx /* Reserve some space */ |
| pushl %ebx |
| pushl %esi |
| |
| movl PARAM1,%esi |
| |
| movl 8(%esi),%edx |
| movl 4(%esi),%ebx |
| movl (%esi),%eax |
| |
| movl $0,-4(%ebp) |
| |
| orl %edx,%edx /* ms bits */ |
| js L_round /* Already normalized */ |
| jnz L_shift_1 /* Shift left 1 - 31 bits */ |
| |
| movl %ebx,%edx |
| movl %eax,%ebx |
| xorl %eax,%eax |
| movl $-32,-4(%ebp) |
| |
| /* We need to shift left by 1 - 31 bits */ |
| L_shift_1: |
| bsrl %edx,%ecx /* get the required shift in %ecx */ |
| subl $31,%ecx |
| negl %ecx |
| subl %ecx,-4(%ebp) |
| shld %cl,%ebx,%edx |
| shld %cl,%eax,%ebx |
| shl %cl,%eax |
| |
| L_round: |
| testl $0x80000000,%eax |
| jz L_exit |
| |
| addl $1,%ebx |
| adcl $0,%edx |
| jnz L_exit |
| |
| movl $0x80000000,%edx |
| incl -4(%ebp) |
| |
| L_exit: |
| movl %edx,8(%esi) |
| movl %ebx,4(%esi) |
| movl %eax,(%esi) |
| |
| movl -4(%ebp),%eax |
| |
| popl %esi |
| popl %ebx |
| leave |
| ret |
| |
| |
| |
| |
| ENTRY(norm_Xsig) |
| pushl %ebp |
| movl %esp,%ebp |
| pushl %ebx /* Reserve some space */ |
| pushl %ebx |
| pushl %esi |
| |
| movl PARAM1,%esi |
| |
| movl 8(%esi),%edx |
| movl 4(%esi),%ebx |
| movl (%esi),%eax |
| |
| movl $0,-4(%ebp) |
| |
| orl %edx,%edx /* ms bits */ |
| js L_n_exit /* Already normalized */ |
| jnz L_n_shift_1 /* Shift left 1 - 31 bits */ |
| |
| movl %ebx,%edx |
| movl %eax,%ebx |
| xorl %eax,%eax |
| movl $-32,-4(%ebp) |
| |
| orl %edx,%edx /* ms bits */ |
| js L_n_exit /* Normalized now */ |
| jnz L_n_shift_1 /* Shift left 1 - 31 bits */ |
| |
| movl %ebx,%edx |
| movl %eax,%ebx |
| xorl %eax,%eax |
| addl $-32,-4(%ebp) |
| jmp L_n_exit /* Might not be normalized, |
| but shift no more. */ |
| |
| /* We need to shift left by 1 - 31 bits */ |
| L_n_shift_1: |
| bsrl %edx,%ecx /* get the required shift in %ecx */ |
| subl $31,%ecx |
| negl %ecx |
| subl %ecx,-4(%ebp) |
| shld %cl,%ebx,%edx |
| shld %cl,%eax,%ebx |
| shl %cl,%eax |
| |
| L_n_exit: |
| movl %edx,8(%esi) |
| movl %ebx,4(%esi) |
| movl %eax,(%esi) |
| |
| movl -4(%ebp),%eax |
| |
| popl %esi |
| popl %ebx |
| leave |
| ret |
| |
