83 lines
2.1 KiB
ArmAsm
83 lines
2.1 KiB
ArmAsm
/* 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) 1992-2014 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 Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 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 Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the GNU MP Library. If not, see <http://www.gnu.org/licenses/>. */
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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 "sysdep.h"
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#include "asm-syntax.h"
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TEXT
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ENTRY(__mpn_sub_n)
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/* Save used registers on the stack. */
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movel R(d2),MEM_PREDEC(sp)
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cfi_adjust_cfa_offset (4)
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movel R(a2),MEM_PREDEC(sp)
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cfi_adjust_cfa_offset (4)
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cfi_rel_offset (R(d2), 4)
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cfi_rel_offset (R(a2), 0)
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/* Copy the arguments to registers. Better use movem? */
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movel MEM_DISP(sp,12),R(a2)
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movel MEM_DISP(sp,16),R(a0)
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movel MEM_DISP(sp,20),R(a1)
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movel MEM_DISP(sp,24),R(d2)
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eorw #1,R(d2)
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lsrl #1,R(d2)
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bcc L(L1)
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subql #1,R(d2) /* clears cy as side effect */
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L(Loop:)
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movel MEM_POSTINC(a0),R(d0)
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movel MEM_POSTINC(a1),R(d1)
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subxl R(d1),R(d0)
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movel R(d0),MEM_POSTINC(a2)
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L(L1:) movel MEM_POSTINC(a0),R(d0)
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movel MEM_POSTINC(a1),R(d1)
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subxl R(d1),R(d0)
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movel R(d0),MEM_POSTINC(a2)
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dbf R(d2),L(Loop) /* loop until 16 lsb of %4 == -1 */
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subxl R(d0),R(d0) /* d0 <= -cy; save cy as 0 or -1 in d0 */
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subl #0x10000,R(d2)
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bcs L(L2)
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addl R(d0),R(d0) /* restore cy */
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bra L(Loop)
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L(L2:)
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negl R(d0)
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/* Restore used registers from stack frame. */
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movel MEM_POSTINC(sp),R(a2)
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cfi_adjust_cfa_offset (-4)
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cfi_restore (R(a2))
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movel MEM_POSTINC(sp),R(d2)
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cfi_adjust_cfa_offset (-4)
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cfi_restore (R(d2))
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rts
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END(__mpn_sub_n)
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