77 lines
2.1 KiB
ArmAsm
77 lines
2.1 KiB
ArmAsm
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/* mc68020 __mpn_sub_n -- Subtract two limb vectors of the same length > 0 and
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store difference in a third limb vector.
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Copyright (C) 1992, 1994 Free Software Foundation, Inc.
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This file is part of the GNU MP Library.
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The GNU MP Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Library General Public License as published by
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the Free Software Foundation; either version 2 of the License, or (at your
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option) any later version.
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The GNU MP Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
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License for more details.
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You should have received a copy of the GNU Library General Public License
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along with the GNU MP Library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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/*
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INPUT PARAMETERS
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res_ptr (sp + 4)
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s1_ptr (sp + 8)
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s2_ptr (sp + 16)
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size (sp + 12)
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*/
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#include "asm-syntax.h"
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TEXT
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ALIGN
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GLOBL ___mpn_sub_n
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LAB(___mpn_sub_n)
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/* Save used registers on the stack. */
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INSN2(move,l ,MEM_PREDEC(sp),d2)
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INSN2(move,l ,MEM_PREDEC(sp),a2)
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/* Copy the arguments to registers. Better use movem? */
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INSN2(move,l ,a2,MEM_DISP(sp,12))
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INSN2(move,l ,a0,MEM_DISP(sp,16))
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INSN2(move,l ,a1,MEM_DISP(sp,20))
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INSN2(move,l ,d2,MEM_DISP(sp,24))
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INSN2(eor,w ,d2,#1)
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INSN2(lsr,l ,d2,#1)
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bcc L1
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INSN2(subq,l ,d2,#1) /* clears cy as side effect */
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LAB(Loop)
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INSN2(move,l ,d0,MEM_POSTINC(a0))
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INSN2(move,l ,d1,MEM_POSTINC(a1))
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INSN2(subx,l ,d0,d1)
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INSN2(move,l ,MEM_POSTINC(a2),d0)
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LAB(L1) INSN2(move,l ,d0,MEM_POSTINC(a0))
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INSN2(move,l ,d1,MEM_POSTINC(a1))
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INSN2(subx,l ,d0,d1)
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INSN2(move,l ,MEM_POSTINC(a2),d0)
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dbf d2,Loop /* loop until 16 lsb of %4 == -1 */
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INSN2(subx,l ,d0,d0) /* d0 <= -cy; save cy as 0 or -1 in d0 */
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INSN2(sub,l ,d2,#0x10000)
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bcs L2
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INSN2(add,l ,d0,d0) /* restore cy */
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bra Loop
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LAB(L2)
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INSN1(neg,l ,d0)
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/* Restore used registers from stack frame. */
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INSN2(move,l ,a2,MEM_POSTINC(sp))
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INSN2(move,l ,d2,MEM_POSTINC(sp))
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rts
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