| /* |
| * (c) Copyright 1986 HEWLETT-PACKARD COMPANY |
| * |
| * To anyone who acknowledges that this file is provided "AS IS" |
| * without any express or implied warranty: |
| * permission to use, copy, modify, and distribute this file |
| * for any purpose is hereby granted without fee, provided that |
| * the above copyright notice and this notice appears in all |
| * copies, and that the name of Hewlett-Packard Company not be |
| * used in advertising or publicity pertaining to distribution |
| * of the software without specific, written prior permission. |
| * Hewlett-Packard Company makes no representations about the |
| * suitability of this software for any purpose. |
| */ |
| |
| /* HPUX_ID: @(#) $Revision: 1.1 $ */ |
| /* |
| * memcpy(s1, s2, n) |
| * |
| * Copy n characters from s2 to s1; returns s1. |
| */ |
| |
| #define d_addr arg0 |
| #define s_addr arg1 |
| #define count arg2 |
| #define tmp5 arg3 |
| #define tmp1 r19 |
| #define tmp2 r20 |
| #define tmp3 r21 |
| #define tmp4 r22 |
| #define tmp6 r31 |
| |
| #include "DEFS.h" |
| |
| ENTRY(memcpy) |
| comib,>= 5,count,byteloop /* If count is <= 6 don't get fancy.*/ |
| movb,=,n d_addr,ret0,done /* The return value is defined to be the value of d_addr. DELAY SLOT */ |
| /* if d_addr is null then exit */ |
| extru s_addr,31,2,tmp1 /* Extract the low two bits of the source address. */ |
| extru d_addr,31,2,tmp2 /* Extract the low two bits of the destination address. */ |
| add count,tmp2,count /* pre increment the count to adjust for alignment of s1 */ |
| comb,<> tmp2,tmp1,not_aligned /* see if s1 is aligned w.r.t. s2. */ |
| dep 0,31,2,s_addr /* Compute the word address of the source. DELAY SLOT. */ |
| |
| /* aligned */ |
| |
| /* We will now begin the 16 byte at a time word move if count >= 16 ! */ |
| /* Else we will branch to the 4 byte-at-a time word move ! */ |
| |
| addibt,<,n -16,count,chekchunk /* If count < 16 then we can't move 16 byte chunks ! */ |
| /* actually we can legally move 13 or more bytes on the first loop. */ |
| /* These loads and stores are done so as to prevent processor interlock. */ |
| chunks: |
| ldwm 16(0,s_addr),tmp1 /* tmp1 = *s_addr s_addr += 16 */ |
| ldw -12(0,s_addr),tmp2 /* tmp2 = 2nd word */ |
| ldw -8(0,s_addr),tmp3 /* tmp3 = 3rd word */ |
| ldw -4(0,s_addr),tmp4 /* tmp4 = 4th word */ |
| /* Now store the results ! */ |
| stbys,b,m tmp1,4(0,d_addr) /* tmp1 = 1st word stored d_addr += 16 also take care of front porch. */ |
| stwm tmp2,4(0,d_addr) /* tmp2 = 2nd word stored. */ |
| stwm tmp3,4(0,d_addr) /* tmp3 = 3rd word stored. */ |
| addibf,< -16,count,chunks /* If count is still >= 16 do another loop. */ |
| stwm tmp4,4(0,d_addr) /* tmp4 = 4th word stored. DELAY SLOT */ |
| |
| chekchunk: |
| addibt,<,n 12,count,back_porch /* since the count is already decremented by -16 we're testing */ |
| /* to see if there are at least 4 bytes left ? */ |
| subchunk: |
| ldws,ma 4(s_addr),tmp1 /* tmp1 = *s_addr++ */ |
| addibf,< -4,count,subchunk /* count -= 4 */ |
| stbys,b,m tmp1,4(d_addr) /* *d_addr++ = tmp1 */ |
| |
| |
| back_porch: |
| addibt,=,n 4,count,done /* if count = 0 we're, of course, done ! */ |
| ldws 0(s_addr),tmp1 /* load up the back_porch */ |
| add d_addr,count,d_addr/* final store address is +1 too high ! */ |
| bv 0(r2) /* return--were done. */ |
| stbys,e tmp1,0(d_addr) /* kerplunk! whew ! */ |
| |
| /* Begin non_aligned code. (no refrence to politics) */ |
| not_aligned: |
| sub,>= tmp2,tmp1,tmp3 /* compute the shift quantity again and skip the load if tmp2 > tmp1. */ |
| ldwm 4(0,s_addr),tmp1 /* load up the first word from the source. tmp1 = *s_addr++ */ |
| zdep tmp3,28,29,tmp4 /* compute the number of bits to shift based on the number of bytes above. */ |
| mtctl tmp4,11 /* load the shift count into cr11 = shift count register. */ |
| |
| addibt,<,n -16,count,chkchnk2 /* first step in pre adjustment of count for looping. */ |
| |
| chunk2: |
| ldwm 16(0,s_addr),tmp2 /* get either first or second word . tmp2 = *s_addr++ */ |
| ldw -12(s_addr),tmp3 |
| ldw -8(s_addr),tmp4 |
| ldw -4(s_addr),tmp5 |
| vshd tmp1,tmp2,tmp6 /* position data ! */ |
| stbys,b,m tmp6,4(0,d_addr) /* store ! */ |
| |
| vshd tmp2,tmp3,tmp6 /* position data ! */ |
| stwm tmp6,4(0,d_addr) /* store ! */ |
| |
| vshd tmp3,tmp4,tmp6 /* position data ! */ |
| stwm tmp6,4(0,d_addr) /* store ! */ |
| |
| vshd tmp4,tmp5,tmp6 /* position data ! */ |
| stwm tmp6,4(0,d_addr) /* store the data ! */ |
| addibf,< -16,count,chunk2 /* If count is still >= 16 do another loop. */ |
| copy tmp5,tmp1 |
| |
| |
| chkchnk2: |
| addibt,<,n 12,count,bp_0 /* if we don't have 4 bytes left then do the back porch (bp_0) */ |
| |
| subchnk2: |
| ldwm 4(0,s_addr),tmp2 /* get next word ! */ |
| vshd tmp1,tmp2,tmp3 /* position data ! */ |
| addibt,< -4,count,bp_1 /* decrement count and when count < 4 goto back_porch (bp_1) */ |
| stbys,b,m tmp3,4(0,d_addr) /* store ! */ |
| |
| ldwm 4(0,s_addr),tmp1 /* get 4th word ! */ |
| vshd tmp2,tmp1,tmp3 /* position data ! */ |
| addib,>= -4,count,subchnk2 /* decrement count and when count <= 4 go to back porch (bp_2) */ |
| stbys,b,m tmp3,4(0,d_addr) /* store the data ! */ |
| |
| bp_0: copy tmp1,tmp2 /* switch registers used in the shift process. */ |
| bp_1: addibt,<=,n 4,count,done /* if count = -4 this implies that count = 0 -> done */ |
| add d_addr,count,d_addr /* bump destination address to be +1 too high ! */ |
| mfctl sar,tmp3 /* suppress final ldwm unless result used */ |
| extru tmp3,28,2,tmp3 /* convert bitshift to byteshift */ |
| sub,<= count,tmp3,r0 /* bytes unused if (count-byteshift <= 0*/ |
| |
| ldwm 4(0,s_addr),tmp1 /* get final word ! */ |
| vshd tmp2,tmp1,tmp3 /* position data ! */ |
| bv 0(r2) /* return */ |
| stbys,e tmp3,0(0,d_addr) /* store the data ! */ |
| |
| /* here we do ye old byte-at-a-time moves. */ |
| byteloop: |
| comb,>=,n 0,count,done |
| |
| encore: |
| ldbs,ma 1(s_addr),tmp1 |
| addibf,= -1,count,encore |
| stbs,ma tmp1,1(d_addr) |
| |
| done: |
| EXIT(memcpy) |
