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