1dnl PPC-32 mpn_divrem_2 -- Divide an mpn number by a normalized 2-limb number. 2 3dnl Copyright 2007, 2008, 2012 Free Software Foundation, Inc. 4 5dnl This file is part of the GNU MP Library. 6dnl 7dnl The GNU MP Library is free software; you can redistribute it and/or modify 8dnl it under the terms of either: 9dnl 10dnl * the GNU Lesser General Public License as published by the Free 11dnl Software Foundation; either version 3 of the License, or (at your 12dnl option) any later version. 13dnl 14dnl or 15dnl 16dnl * the GNU General Public License as published by the Free Software 17dnl Foundation; either version 2 of the License, or (at your option) any 18dnl later version. 19dnl 20dnl or both in parallel, as here. 21dnl 22dnl The GNU MP Library is distributed in the hope that it will be useful, but 23dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 24dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 25dnl for more details. 26dnl 27dnl You should have received copies of the GNU General Public License and the 28dnl GNU Lesser General Public License along with the GNU MP Library. If not, 29dnl see https://www.gnu.org/licenses/. 30 31include(`../config.m4') 32 33C cycles/limb 34C norm frac 35C 7410 ~36.5 ~36.5 36C 744x, 745x 29 29 37 38C INPUT PARAMETERS 39C qp = r3 40C fn = r4 41C up = r5 42C un = r6 43C d = r7 44 45C TODO 46C * Decrease register usage. 47C * Make sure mul operands and optimal for early-out. 48C * Check that things work well for a shared library build. 49C * Write an invert_limb, perhaps inline, perhaps as a private call. Or at 50C least vastly improve the current __udiv_qrnnd_c based code. 51 52 53ASM_START() 54PROLOGUE(mpn_divrem_2) 55 stwu r1, -32(r1) 56 slwi r0, r6, 2 57 add r5, r5, r0 58 stmw r28, 8(r1) 59 addi r29, r5, -8 C up = up_param + un - 2 60 lwz r10, 4(r7) 61 lwz r12, 4(r29) 62 addi r8, r3, -12 63 lwz r7, 0(r7) 64 cmplw cr7, r12, r10 65 lwz r28, 0(r29) 66 blt- cr7, L(2) 67 bgt+ cr7, L(4) 68 cmplw cr7, r28, r7 69 blt- cr7, L(2) 70L(4): subfc r28, r7, r28 71 subfe r12, r10, r12 72 li r3, 1 73 b L(6) 74L(2): li r3, 0 75 76L(6): add r0, r4, r6 77 addic. r30, r0, -2 78 ble- cr0, L(ret) 79 80 slwi r9, r0, 2 81 add r8, r8, r9 C rp += un + fn 82 mtctr r30 83 84C Compute di from d1 85 srwi r11, r10, 16 86 nor r0, r10, r10 87 divwu r31, r0, r11 88 rlwinm r5, r10, 0, 16, 31 89 mullw r9, r11, r31 90 mullw r6, r5, r31 91 subf r0, r9, r0 92 slwi r0, r0, 16 93 ori r0, r0, 65535 94 cmplw cr7, r0, r6 95 bge- cr7, L(9) 96 add r0, r0, r10 97 cmplw cr7, r0, r10 98 cmplw cr6, r6, r0 99 addi r31, r31, -1 C q1-- 100 crorc 28, 28, 25 101 bc+ 12, 28, L(9) 102 addi r31, r31, -1 C q1-- 103 add r0, r0, r10 104L(9): subf r0, r6, r0 105 divwu r6, r0, r11 106 mullw r9, r11, r6 107 mullw r11, r5, r6 108 subf r0, r9, r0 109 slwi r0, r0, 16 110 ori r0, r0, 65535 111 cmplw cr7, r0, r11 112 bge- cr7, L(13) 113 add r0, r0, r10 114 cmplw cr7, r0, r10 115 cmplw cr6, r11, r0 116 addi r6, r6, -1 C q0-- 117 crorc 28, 28, 25 118 bc+ 12, 28, L(13) 119C add r0, r0, r10 C final remainder 120 addi r6, r6, -1 C q0-- 121L(13): rlwimi r6, r31, 16, 0, 15 C assemble final quotient 122 123C Adjust di by including d0 124 mullw r9, r10, r6 C t0 = LO(di * d1) 125 addc r11, r9, r7 126 subfe r0, r1, r1 127 mulhwu r9, r6, r7 C s1 = HI(di * d0) 128 addc r9, r11, r9 129 addze. r0, r0 130 blt cr0, L(17) 131L(18): subfc r9, r10, r9 132 addi r6, r6, -1 133 addme. r0, r0 134 bge+ cr0, L(18) 135L(17): 136 137C r0 r3 r4 r5 r6 r7 r8 r9 r10 r11 r12 r28 r29 r30 r31 138C msl di d0 qp d1 fn up un 139L(loop): 140 mullw r0, r12, r6 C q0 = LO(n2 * di) 141 cmpw cr7, r30, r4 142 addc r31, r0, r28 C q0 += n1 143 mulhwu r9, r12, r6 C q = HI(n2 * di) 144 adde r12, r9, r12 C q += n2 145 addi r30, r30, -1 146 mullw r0, r10, r12 C d1 * q 147 li r9, 0 148 subf r0, r0, r28 C n1 -= d1 * q 149 addi r5, r12, 1 150 ble- cr7, L(23) 151 lwzu r9, -4(r29) 152L(23): mullw r11, r12, r7 C t0 = LO(d0 * q) 153 subfc r28, r7, r9 C n0 -= d0 154 subfe r0, r10, r0 C n1 -= d1 155 mulhwu r12, r12, r7 C t1 = HI(d0 * q) 156 subfc r28, r11, r28 C n0 -= t0 157 subfe r12, r12, r0 C n1 -= t1 158 cmplw cr7, r12, r31 159 blt+ cr7, L(24) 160 addc r28, r28, r7 161 adde r12, r12, r10 162 addi r5, r5, -1 163L(24): cmplw cr7, r12, r10 164 bge- cr7, L(fix) 165L(bck): stw r5, 0(r8) 166 addi r8, r8, -4 167 bdnz L(loop) 168 169L(ret): stw r28, 0(r29) 170 stw r12, 4(r29) 171 lmw r28, 8(r1) 172 addi r1, r1, 32 173 blr 174 175L(fix): cmplw cr6, r28, r7 176 bgt+ cr7, L(28) 177 blt- cr6, L(bck) 178L(28): subfc r28, r7, r28 179 subfe r12, r10, r12 180 addi r5, r5, 1 181 b L(bck) 182EPILOGUE() 183