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- /*---------------------------------------------------------------------------+
- | 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
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