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89 lines
2.5 KiB
89 lines
2.5 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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.file "shr_Xsig.S" |
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/*---------------------------------------------------------------------------+ |
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| shr_Xsig.S | |
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| | |
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| 12 byte right shift function | |
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| | |
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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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| | |
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| Call from C as: | |
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| void shr_Xsig(Xsig *arg, unsigned nr) | |
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| | |
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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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+---------------------------------------------------------------------------*/ |
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#include "fpu_emu.h" |
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.text |
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SYM_FUNC_START(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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SYM_FUNC_END(shr_Xsig)
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