/* * (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: @(#) $Revision$ */ /* * 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)