88 строки
2.4 KiB
ArmAsm
88 строки
2.4 KiB
ArmAsm
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.file "shr_Xsig.S"
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/*---------------------------------------------------------------------------+
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| shr_Xsig.S |
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| 12 byte right shift function |
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| Copyright (C) 1992,1994,1995 |
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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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| Call from C as: |
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| void shr_Xsig(Xsig *arg, unsigned nr) |
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| Extended shift right function. |
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| Fastest for small shifts. |
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| Shifts the 12 byte quantity pointed to by the first arg (arg) |
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| right by the number of bits specified by the second arg (nr). |
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+---------------------------------------------------------------------------*/
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#include "fpu_emu.h"
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.text
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ENTRY(shr_Xsig)
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push %ebp
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movl %esp,%ebp
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pushl %esi
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movl PARAM2,%ecx
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movl PARAM1,%esi
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cmpl $32,%ecx /* shrd only works for 0..31 bits */
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jnc L_more_than_31
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/* less than 32 bits */
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pushl %ebx
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movl (%esi),%eax /* lsl */
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movl 4(%esi),%ebx /* midl */
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movl 8(%esi),%edx /* msl */
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shrd %cl,%ebx,%eax
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shrd %cl,%edx,%ebx
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shr %cl,%edx
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movl %eax,(%esi)
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movl %ebx,4(%esi)
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movl %edx,8(%esi)
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popl %ebx
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popl %esi
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leave
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ret
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L_more_than_31:
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cmpl $64,%ecx
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jnc L_more_than_63
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subb $32,%cl
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movl 4(%esi),%eax /* midl */
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movl 8(%esi),%edx /* msl */
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shrd %cl,%edx,%eax
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shr %cl,%edx
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movl %eax,(%esi)
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movl %edx,4(%esi)
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movl $0,8(%esi)
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popl %esi
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leave
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ret
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L_more_than_63:
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cmpl $96,%ecx
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jnc L_more_than_95
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subb $64,%cl
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movl 8(%esi),%eax /* msl */
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shr %cl,%eax
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xorl %edx,%edx
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movl %eax,(%esi)
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movl %edx,4(%esi)
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movl %edx,8(%esi)
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popl %esi
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leave
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ret
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L_more_than_95:
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xorl %eax,%eax
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movl %eax,(%esi)
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movl %eax,4(%esi)
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movl %eax,8(%esi)
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popl %esi
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leave
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ret
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