Annotation of OpenXM_contrib/gmp/mpn/m68k/lshift.S, Revision 1.1
1.1 ! maekawa 1: /* mc68020 __mpn_lshift -- Shift left a low-level natural-number integer.
! 2:
! 3: Copyright (C) 1996 Free Software Foundation, Inc.
! 4:
! 5: This file is part of the GNU MP Library.
! 6:
! 7: The GNU MP Library is free software; you can redistribute it and/or modify
! 8: it under the terms of the GNU Library General Public License as published by
! 9: the Free Software Foundation; either version 2 of the License, or (at your
! 10: option) any later version.
! 11:
! 12: The GNU MP Library is distributed in the hope that it will be useful, but
! 13: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
! 14: or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
! 15: License for more details.
! 16:
! 17: You should have received a copy of the GNU Library General Public License
! 18: along with the GNU MP Library; see the file COPYING.LIB. If not, write to
! 19: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
! 20: MA 02111-1307, USA. */
! 21:
! 22: /*
! 23: INPUT PARAMETERS
! 24: res_ptr (sp + 4)
! 25: s_ptr (sp + 8)
! 26: s_size (sp + 16)
! 27: cnt (sp + 12)
! 28: */
! 29:
! 30: #include "sysdep.h"
! 31: #include "asm-syntax.h"
! 32:
! 33: #define res_ptr a1
! 34: #define s_ptr a0
! 35: #define s_size d6
! 36: #define cnt d4
! 37:
! 38: TEXT
! 39: ALIGN
! 40: GLOBL C_SYMBOL_NAME(__mpn_lshift)
! 41:
! 42: C_SYMBOL_NAME(__mpn_lshift:)
! 43: PROLOG(__mpn_lshift)
! 44:
! 45: /* Save used registers on the stack. */
! 46: moveml R(d2)-R(d6)/R(a2),MEM_PREDEC(sp)
! 47:
! 48: /* Copy the arguments to registers. */
! 49: movel MEM_DISP(sp,28),R(res_ptr)
! 50: movel MEM_DISP(sp,32),R(s_ptr)
! 51: movel MEM_DISP(sp,36),R(s_size)
! 52: movel MEM_DISP(sp,40),R(cnt)
! 53:
! 54: moveql #1,R(d5)
! 55: cmpl R(d5),R(cnt)
! 56: bne L(Lnormal)
! 57: cmpl R(s_ptr),R(res_ptr)
! 58: bls L(Lspecial) /* jump if s_ptr >= res_ptr */
! 59: #if (defined (__mc68020__) || defined (__NeXT__) || defined(mc68020))
! 60: lea MEM_INDX1(s_ptr,s_size,l,4),R(a2)
! 61: #else /* not mc68020 */
! 62: movel R(s_size),R(d0)
! 63: asll #2,R(d0)
! 64: lea MEM_INDX(s_ptr,d0,l),R(a2)
! 65: #endif
! 66: cmpl R(res_ptr),R(a2)
! 67: bls L(Lspecial) /* jump if res_ptr >= s_ptr + s_size */
! 68:
! 69: L(Lnormal:)
! 70: moveql #32,R(d5)
! 71: subl R(cnt),R(d5)
! 72:
! 73: #if (defined (__mc68020__) || defined (__NeXT__) || defined(mc68020))
! 74: lea MEM_INDX1(s_ptr,s_size,l,4),R(s_ptr)
! 75: lea MEM_INDX1(res_ptr,s_size,l,4),R(res_ptr)
! 76: #else /* not mc68000 */
! 77: movel R(s_size),R(d0)
! 78: asll #2,R(d0)
! 79: addl R(s_size),R(s_ptr)
! 80: addl R(s_size),R(res_ptr)
! 81: #endif
! 82: movel MEM_PREDEC(s_ptr),R(d2)
! 83: movel R(d2),R(d0)
! 84: lsrl R(d5),R(d0) /* compute carry limb */
! 85:
! 86: lsll R(cnt),R(d2)
! 87: movel R(d2),R(d1)
! 88: subql #1,R(s_size)
! 89: beq L(Lend)
! 90: lsrl #1,R(s_size)
! 91: bcs L(L1)
! 92: subql #1,R(s_size)
! 93:
! 94: L(Loop:)
! 95: movel MEM_PREDEC(s_ptr),R(d2)
! 96: movel R(d2),R(d3)
! 97: lsrl R(d5),R(d3)
! 98: orl R(d3),R(d1)
! 99: movel R(d1),MEM_PREDEC(res_ptr)
! 100: lsll R(cnt),R(d2)
! 101: L(L1:)
! 102: movel MEM_PREDEC(s_ptr),R(d1)
! 103: movel R(d1),R(d3)
! 104: lsrl R(d5),R(d3)
! 105: orl R(d3),R(d2)
! 106: movel R(d2),MEM_PREDEC(res_ptr)
! 107: lsll R(cnt),R(d1)
! 108:
! 109: dbf R(s_size),L(Loop)
! 110: subl #0x10000,R(s_size)
! 111: bcc L(Loop)
! 112:
! 113: L(Lend:)
! 114: movel R(d1),MEM_PREDEC(res_ptr) /* store least significant limb */
! 115:
! 116: /* Restore used registers from stack frame. */
! 117: moveml MEM_POSTINC(sp),R(d2)-R(d6)/R(a2)
! 118: rts
! 119:
! 120: /* We loop from least significant end of the arrays, which is only
! 121: permissable if the source and destination don't overlap, since the
! 122: function is documented to work for overlapping source and destination. */
! 123:
! 124: L(Lspecial:)
! 125: clrl R(d0) /* initialize carry */
! 126: eorw #1,R(s_size)
! 127: lsrl #1,R(s_size)
! 128: bcc L(LL1)
! 129: subql #1,R(s_size)
! 130:
! 131: L(LLoop:)
! 132: movel MEM_POSTINC(s_ptr),R(d2)
! 133: addxl R(d2),R(d2)
! 134: movel R(d2),MEM_POSTINC(res_ptr)
! 135: L(LL1:)
! 136: movel MEM_POSTINC(s_ptr),R(d2)
! 137: addxl R(d2),R(d2)
! 138: movel R(d2),MEM_POSTINC(res_ptr)
! 139:
! 140: dbf R(s_size),L(LLoop)
! 141: addxl R(d0),R(d0) /* save cy in lsb */
! 142: subl #0x10000,R(s_size)
! 143: bcs L(LLend)
! 144: lsrl #1,R(d0) /* restore cy */
! 145: bra L(LLoop)
! 146:
! 147: L(LLend:)
! 148: /* Restore used registers from stack frame. */
! 149: moveml MEM_POSTINC(sp),R(d2)-R(d6)/R(a2)
! 150: rts
! 151: EPILOG(__mpn_lshift)
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