1/* 2 * (c) Copyright 1986 HEWLETT-PACKARD COMPANY 3 * 4 * To anyone who acknowledges that this file is provided "AS IS" 5 * without any express or implied warranty: 6 * permission to use, copy, modify, and distribute this file 7 * for any purpose is hereby granted without fee, provided that 8 * the above copyright notice and this notice appears in all 9 * copies, and that the name of Hewlett-Packard Company not be 10 * used in advertising or publicity pertaining to distribution 11 * of the software without specific, written prior permission. 12 * Hewlett-Packard Company makes no representations about the 13 * suitability of this software for any purpose. 14 */ 15 16/* HPUX_ID: @(#) $Revision$ */ 17/* 18 * memcpy(s1, s2, n) 19 * 20 * Copy n characters from s2 to s1; returns s1. 21 */ 22 23#define d_addr arg0 24#define s_addr arg1 25#define count arg2 26#define tmp5 arg3 27#define tmp1 r19 28#define tmp2 r20 29#define tmp3 r21 30#define tmp4 r22 31#define tmp6 r31 32 33#include "DEFS.h" 34 35ENTRY(memcpy) 36 comib,>= 5,count,byteloop /* If count is <= 6 don't get fancy.*/ 37 movb,=,n d_addr,ret0,done /* The return value is defined to be the value of d_addr. DELAY SLOT */ 38 /* if d_addr is null then exit */ 39 extru s_addr,31,2,tmp1 /* Extract the low two bits of the source address. */ 40 extru d_addr,31,2,tmp2 /* Extract the low two bits of the destination address. */ 41 add count,tmp2,count /* pre increment the count to adjust for alignment of s1 */ 42 comb,<> tmp2,tmp1,not_aligned /* see if s1 is aligned w.r.t. s2. */ 43 dep 0,31,2,s_addr /* Compute the word address of the source. DELAY SLOT. */ 44 45/* aligned */ 46 47/* We will now begin the 16 byte at a time word move if count >= 16 ! */ 48/* Else we will branch to the 4 byte-at-a time word move ! */ 49 50 addibt,<,n -16,count,chekchunk /* If count < 16 then we can't move 16 byte chunks ! */ 51 /* actually we can legally move 13 or more bytes on the first loop. */ 52 /* These loads and stores are done so as to prevent processor interlock. */ 53chunks: 54 ldwm 16(0,s_addr),tmp1 /* tmp1 = *s_addr s_addr += 16 */ 55 ldw -12(0,s_addr),tmp2 /* tmp2 = 2nd word */ 56 ldw -8(0,s_addr),tmp3 /* tmp3 = 3rd word */ 57 ldw -4(0,s_addr),tmp4 /* tmp4 = 4th word */ 58 /* Now store the results ! */ 59 stbys,b,m tmp1,4(0,d_addr) /* tmp1 = 1st word stored d_addr += 16 also take care of front porch. */ 60 stwm tmp2,4(0,d_addr) /* tmp2 = 2nd word stored. */ 61 stwm tmp3,4(0,d_addr) /* tmp3 = 3rd word stored. */ 62 addibf,< -16,count,chunks /* If count is still >= 16 do another loop. */ 63 stwm tmp4,4(0,d_addr) /* tmp4 = 4th word stored. DELAY SLOT */ 64 65chekchunk: 66 addibt,<,n 12,count,back_porch /* since the count is already decremented by -16 we're testing */ 67 /* to see if there are at least 4 bytes left ? */ 68subchunk: 69 ldws,ma 4(s_addr),tmp1 /* tmp1 = *s_addr++ */ 70 addibf,< -4,count,subchunk /* count -= 4 */ 71 stbys,b,m tmp1,4(d_addr) /* *d_addr++ = tmp1 */ 72 73 74back_porch: 75 addibt,=,n 4,count,done /* if count = 0 we're, of course, done ! */ 76 ldws 0(s_addr),tmp1 /* load up the back_porch */ 77 add d_addr,count,d_addr/* final store address is +1 too high ! */ 78 bv 0(r2) /* return--were done. */ 79 stbys,e tmp1,0(d_addr) /* kerplunk! whew ! */ 80 81/* Begin non_aligned code. (no refrence to politics) */ 82not_aligned: 83 sub,>= tmp2,tmp1,tmp3 /* compute the shift quantity again and skip the load if tmp2 > tmp1. */ 84 ldwm 4(0,s_addr),tmp1 /* load up the first word from the source. tmp1 = *s_addr++ */ 85 zdep tmp3,28,29,tmp4 /* compute the number of bits to shift based on the number of bytes above. */ 86 mtctl tmp4,11 /* load the shift count into cr11 = shift count register. */ 87 88 addibt,<,n -16,count,chkchnk2 /* first step in pre adjustment of count for looping. */ 89 90chunk2: 91 ldwm 16(0,s_addr),tmp2 /* get either first or second word . tmp2 = *s_addr++ */ 92 ldw -12(s_addr),tmp3 93 ldw -8(s_addr),tmp4 94 ldw -4(s_addr),tmp5 95 vshd tmp1,tmp2,tmp6 /* position data ! */ 96 stbys,b,m tmp6,4(0,d_addr) /* store ! */ 97 98 vshd tmp2,tmp3,tmp6 /* position data ! */ 99 stwm tmp6,4(0,d_addr) /* store ! */ 100 101 vshd tmp3,tmp4,tmp6 /* position data ! */ 102 stwm tmp6,4(0,d_addr) /* store ! */ 103 104 vshd tmp4,tmp5,tmp6 /* position data ! */ 105 stwm tmp6,4(0,d_addr) /* store the data ! */ 106 addibf,< -16,count,chunk2 /* If count is still >= 16 do another loop. */ 107 copy tmp5,tmp1 108 109 110chkchnk2: 111 addibt,<,n 12,count,bp_0 /* if we don't have 4 bytes left then do the back porch (bp_0) */ 112 113subchnk2: 114 ldwm 4(0,s_addr),tmp2 /* get next word ! */ 115 vshd tmp1,tmp2,tmp3 /* position data ! */ 116 addibt,< -4,count,bp_1 /* decrement count and when count < 4 goto back_porch (bp_1) */ 117 stbys,b,m tmp3,4(0,d_addr) /* store ! */ 118 119 ldwm 4(0,s_addr),tmp1 /* get 4th word ! */ 120 vshd tmp2,tmp1,tmp3 /* position data ! */ 121 addib,>= -4,count,subchnk2 /* decrement count and when count <= 4 go to back porch (bp_2) */ 122 stbys,b,m tmp3,4(0,d_addr) /* store the data ! */ 123 124bp_0: copy tmp1,tmp2 /* switch registers used in the shift process. */ 125bp_1: addibt,<=,n 4,count,done /* if count = -4 this implies that count = 0 -> done */ 126 add d_addr,count,d_addr /* bump destination address to be +1 too high ! */ 127 mfctl sar,tmp3 /* suppress final ldwm unless result used */ 128 extru tmp3,28,2,tmp3 /* convert bitshift to byteshift */ 129 sub,<= count,tmp3,r0 /* bytes unused if (count-byteshift <= 0*/ 130 131 ldwm 4(0,s_addr),tmp1 /* get final word ! */ 132 vshd tmp2,tmp1,tmp3 /* position data ! */ 133 bv 0(r2) /* return */ 134 stbys,e tmp3,0(0,d_addr) /* store the data ! */ 135 136/* here we do ye old byte-at-a-time moves. */ 137byteloop: 138 comb,>=,n 0,count,done 139 140encore: 141 ldbs,ma 1(s_addr),tmp1 142 addibf,= -1,count,encore 143 stbs,ma tmp1,1(d_addr) 144 145done: 146EXIT(memcpy) 147
