1dnl PowerPC-32 mpn_rshift -- Shift a number right. 2 3dnl Copyright 1995, 1998, 2000, 2002, 2003, 2004, 2005 Free Software 4dnl Foundation, Inc. 5 6dnl This file is part of the GNU MP Library. 7 8dnl The GNU MP Library is free software; you can redistribute it and/or modify 9dnl it under the terms of the GNU Lesser General Public License as published 10dnl by the Free Software Foundation; either version 3 of the License, or (at 11dnl your option) any later version. 12 13dnl The GNU MP Library is distributed in the hope that it will be useful, but 14dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 15dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 16dnl License for more details. 17 18dnl You should have received a copy of the GNU Lesser General Public License 19dnl along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. 20 21include(`../config.m4') 22 23C cycles/limb 24C 603e: ? 25C 604e: 3.0 26C 75x (G3): 3.0 27C 7400,7410 (G4): 3.0 28C 7445,7455 (G4+): 2.5 29C 7447,7457 (G4+): 2.25 30C power4/ppc970: 2.5 31C power5: 2.5 32 33C INPUT PARAMETERS 34C rp r3 35C up r4 36C n r5 37C cnt r6 38 39ASM_START() 40PROLOGUE(mpn_rshift) 41 cmpwi cr0, r5, 12 C more than 12 limbs? 42 addi r7, r3, -4 C dst-4 43 bgt L(BIG) C branch if more than 12 limbs 44 45 mtctr r5 C copy size into CTR 46 subfic r8, r6, 32 47 lwz r11, 0(r4) C load first s1 limb 48 slw r3, r11, r8 C compute function return value 49 bdz L(end1) 50 51L(oop): lwzu r10, 4(r4) 52 srw r9, r11, r6 53 slw r12, r10, r8 54 or r9, r9, r12 55 stwu r9, 4(r7) 56 bdz L(end2) 57 lwzu r11, 4(r4) 58 srw r9, r10, r6 59 slw r12, r11, r8 60 or r9, r9, r12 61 stwu r9, 4(r7) 62 bdnz L(oop) 63 64L(end1): 65 srw r0, r11, r6 66 stw r0, 4(r7) 67 blr 68L(end2): 69 srw r0, r10, r6 70 stw r0, 4(r7) 71 blr 72 73L(BIG): 74 stmw r24, -32(r1) C save registers we are supposed to preserve 75 lwz r9, 0(r4) 76 subfic r8, r6, 32 77 slw r3, r9, r8 C compute function return value 78 srw r0, r9, r6 79 addi r5, r5, -1 80 81 andi. r10, r5, 3 C count for spill loop 82 beq L(e) 83 mtctr r10 84 lwzu r28, 4(r4) 85 bdz L(xe0) 86 87L(loop0): 88 srw r12, r28, r6 89 slw r24, r28, r8 90 lwzu r28, 4(r4) 91 or r24, r0, r24 92 stwu r24, 4(r7) 93 mr r0, r12 94 bdnz L(loop0) C taken at most once! 95 96L(xe0): srw r12, r28, r6 97 slw r24, r28, r8 98 or r24, r0, r24 99 stwu r24, 4(r7) 100 mr r0, r12 101 102L(e): srwi r5, r5, 2 C count for unrolled loop 103 addi r5, r5, -1 104 mtctr r5 105 lwz r28, 4(r4) 106 lwz r29, 8(r4) 107 lwz r30, 12(r4) 108 lwzu r31, 16(r4) 109 110L(loopU): 111 srw r9, r28, r6 112 slw r24, r28, r8 113 lwz r28, 4(r4) 114 srw r10, r29, r6 115 slw r25, r29, r8 116 lwz r29, 8(r4) 117 srw r11, r30, r6 118 slw r26, r30, r8 119 lwz r30, 12(r4) 120 srw r12, r31, r6 121 slw r27, r31, r8 122 lwzu r31, 16(r4) 123 or r24, r0, r24 124 stw r24, 4(r7) 125 or r25, r9, r25 126 stw r25, 8(r7) 127 or r26, r10, r26 128 stw r26, 12(r7) 129 or r27, r11, r27 130 stwu r27, 16(r7) 131 mr r0, r12 132 bdnz L(loopU) 133 134 srw r9, r28, r6 135 slw r24, r28, r8 136 srw r10, r29, r6 137 slw r25, r29, r8 138 srw r11, r30, r6 139 slw r26, r30, r8 140 srw r12, r31, r6 141 slw r27, r31, r8 142 or r24, r0, r24 143 stw r24, 4(r7) 144 or r25, r9, r25 145 stw r25, 8(r7) 146 or r26, r10, r26 147 stw r26, 12(r7) 148 or r27, r11, r27 149 stw r27, 16(r7) 150 151 stw r12, 20(r7) 152 lmw r24, -32(r1) C restore registers 153 blr 154EPILOGUE(mpn_rshift) 155