1dnl mc68020 mpn_lshift -- mpn left shift. 2 3dnl Copyright 1996, 1999-2003 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 33 34C cycles/limb 35C shift==1 shift>1 36C 68040: 5 12 37 38 39C mp_limb_t mpn_lshift (mp_ptr res_ptr, mp_srcptr s_ptr, mp_size_t s_size, 40C unsigned cnt); 41C 42C The "cnt" parameter is either 16 bits or 32 bits depending on 43C SIZEOF_UNSIGNED (see ABI notes in mpn/m68k/README). The value is of 44C course only 1 to 31. When loaded as 16 bits there's garbage in the upper 45C half, hence the use of cmpw. The shift instructions take the their count 46C modulo 64, so the upper part doesn't matter to them either. 47C 48 49C INPUT PARAMETERS 50C res_ptr (sp + 4) 51C s_ptr (sp + 8) 52C s_size (sp + 12) 53C cnt (sp + 16) 54 55define(res_ptr, `a1') 56define(s_ptr, `a0') 57define(s_size, `d6') 58define(cnt, `d4') 59 60ifdef(`SIZEOF_UNSIGNED',, 61`m4_error(`SIZEOF_UNSIGNED not defined, should be in config.m4 62')') 63 64PROLOGUE(mpn_lshift) 65C Save used registers on the stack. 66 moveml d2-d6/a2, M(-,sp) 67 68C Copy the arguments to registers. 69 movel M(sp,28), res_ptr 70 movel M(sp,32), s_ptr 71 movel M(sp,36), s_size 72ifelse(SIZEOF_UNSIGNED,2, 73` movew M(sp,40), cnt', 74` movel M(sp,40), cnt') 75 76 moveql #1, d5 77 cmpw d5, cnt 78 bne L(Lnormal) 79 cmpl s_ptr, res_ptr 80 bls L(Lspecial) C jump if s_ptr >= res_ptr 81 82ifelse(scale_available_p,1,` 83 lea M(s_ptr,s_size,l,4), a2 84',` 85 movel s_size, d0 86 asll #2, d0 87 lea M(s_ptr,d0,l), a2 88') 89 cmpl res_ptr, a2 90 bls L(Lspecial) C jump if res_ptr >= s_ptr + s_size 91 92L(Lnormal): 93 moveql #32, d5 94 subl cnt, d5 95 96ifelse(scale_available_p,1,` 97 lea M(s_ptr,s_size,l,4), s_ptr 98 lea M(res_ptr,s_size,l,4), res_ptr 99',` 100 movel s_size, d0 101 asll #2, d0 102 addl d0, s_ptr 103 addl d0, res_ptr 104') 105 movel M(-,s_ptr), d2 106 movel d2, d0 107 lsrl d5, d0 C compute carry limb 108 109 lsll cnt, d2 110 movel d2, d1 111 subql #1, s_size 112 beq L(Lend) 113 lsrl #1, s_size 114 bcs L(L1) 115 subql #1, s_size 116 117L(Loop): 118 movel M(-,s_ptr), d2 119 movel d2, d3 120 lsrl d5, d3 121 orl d3, d1 122 movel d1, M(-,res_ptr) 123 lsll cnt, d2 124L(L1): 125 movel M(-,s_ptr), d1 126 movel d1, d3 127 lsrl d5, d3 128 orl d3, d2 129 movel d2, M(-,res_ptr) 130 lsll cnt, d1 131 132 dbf s_size, L(Loop) 133 subl #0x10000, s_size 134 bcc L(Loop) 135 136L(Lend): 137 movel d1, M(-,res_ptr) C store least significant limb 138 139C Restore used registers from stack frame. 140 moveml M(sp,+), d2-d6/a2 141 rts 142 143C We loop from least significant end of the arrays, which is only 144C permissable if the source and destination don't overlap, since the 145C function is documented to work for overlapping source and destination. 146 147L(Lspecial): 148 clrl d0 C initialize carry 149 eorw #1, s_size 150 lsrl #1, s_size 151 bcc L(LL1) 152 subql #1, s_size 153 154L(LLoop): 155 movel M(s_ptr,+), d2 156 addxl d2, d2 157 movel d2, M(res_ptr,+) 158L(LL1): 159 movel M(s_ptr,+), d2 160 addxl d2, d2 161 movel d2, M(res_ptr,+) 162 163 dbf s_size, L(LLoop) 164 addxl d0, d0 C save cy in lsb 165 subl #0x10000, s_size 166 bcs L(LLend) 167 lsrl #1, d0 C restore cy 168 bra L(LLoop) 169 170L(LLend): 171C Restore used registers from stack frame. 172 moveml M(sp,+), d2-d6/a2 173 rts 174 175EPILOGUE(mpn_lshift) 176