/*************************************************************************** * __________ __ ___. * Open \______ \ ____ ____ | | _\_ |__ _______ ___ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ * \/ \/ \/ \/ \/ * $Id$ * * Copyright (C) 2006 by Jens Arnold * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ****************************************************************************/ #include "config.h" .section .icode,"ax",@progbits .align 2 .global _memmove .type _memmove,@function /* Moves bytes of data in memory from to * Regions may overlap. * This version is optimized for speed, and needs the corresponding memcpy * implementation for the forward copy branch. * * arguments: * r4 - destination address * r5 - source address * r6 - length * * return value: * r0 - destination address (like ANSI version) * * register usage: * r0 - data / scratch * r1 - 2nd data / scratch * r2 - scratch * r3 - last long bound / adjusted start address (only if >= 11 bytes) * r4 - current dest address * r5 - source start address * r6 - current source address * * The instruction order is devised in a way to utilize the pipelining * of the SH1 to the max. The routine also tries to utilize fast page mode. */ _memmove: cmp/hi r4,r5 /* source > destination */ bf .backward /* no: backward copy */ mov.l .memcpy_fwd,r0 jmp @r0 mov r4,r7 /* store dest for returning */ .align 2 .memcpy_fwd: .long ___memcpy_fwd_entry .backward: add r6,r4 /* r4 = destination end */ mov #11,r0 cmp/hs r0,r6 /* at least 11 bytes to copy? (ensures 2 aligned longs) */ add #-8,r5 /* adjust for late decrement (max. 2 longs) */ add r5,r6 /* r6 = source end - 8 */ bf .start_b2r /* no: jump directly to byte loop */ mov #-4,r3 /* r3 = 0xfffffffc */ and r6,r3 /* r3 = last source long bound */ cmp/hi r3,r6 /* already aligned? */ bf .end_b1r /* yes: skip leading byte loop */ .loop_b1r: mov.b @(7,r6),r0 /* load byte */ add #-1,r6 /* decrement source addr */ mov.b r0,@-r4 /* store byte */ cmp/hi r3,r6 /* runs r6 down to last long bound */ bt .loop_b1r .end_b1r: mov #3,r1 and r4,r1 /* r1 = dest alignment offset */ mova .jmptab_r,r0 mov.b @(r0,r1),r1 /* select appropriate main loop.. */ add r0,r1 mov r5,r3 /* copy start adress to r3 */ jmp @r1 /* ..and jump to it */ add #7,r3 /* adjust end addr for main loops doing 2 longs/pass */ /** main loops, copying 2 longs per pass to profit from fast page mode **/ /* long aligned destination (fastest) */ .align 2 .loop_do0r: mov.l @r6,r1 /* load first long */ add #-8,r6 /* decrement source addr */ mov.l @(12,r6),r0 /* load second long */ cmp/hi r3,r6 /* runs r6 down to first or second long bound */ mov.l r0,@-r4 /* store second long */ mov.l r1,@-r4 /* store first long; NOT ALIGNED - no speed loss here! */ bt .loop_do0r add #-4,r3 /* readjust end address */ cmp/hi r3,r6 /* first long left? */ bf .start_b2r /* no, jump to trailing byte loop */ mov.l @(4,r6),r0 /* load first long */ add #-4,r6 /* decrement source addr */ bra .start_b2r /* jump to trailing byte loop */ mov.l r0,@-r4 /* store first long */ /* word aligned destination (long + 2) */ .align 2 .loop_do2r: mov.l @r6,r1 /* load first long */ add #-8,r6 /* decrement source addr */ mov.l @(12,r6),r0 /* load second long */ cmp/hi r3,r6 /* runs r6 down to first or second long bound */ mov.w r0,@-r4 /* store low word of second long */ xtrct r1,r0 /* extract low word of first long & high word of second long */ mov.l r0,@-r4 /* and store as long */ shlr16 r1 /* get high word of first long */ mov.w r1,@-r4 /* and store it */ bt .loop_do2r add #-4,r3 /* readjust end address */ cmp/hi r3,r6 /* first long left? */ bf .start_b2r /* no, jump to trailing byte loop */ mov.l @(4,r6),r0 /* load first long & decrement source addr */ add #-4,r6 /* decrement source addr */ mov.w r0,@-r4 /* store low word */ shlr16 r0 /* get high word */ bra .start_b2r /* jump to trailing byte loop */ mov.w r0,@-r4 /* and store it */ /* jumptable for loop selector */ .align 2 .jmptab_r: .byte .loop_do0r - .jmptab_r /* placed in the middle because the SH1 */ .byte .loop_do1r - .jmptab_r /* loads bytes sign-extended. Otherwise */ .byte .loop_do2r - .jmptab_r /* the last loop would be out of reach */ .byte .loop_do3r - .jmptab_r /* of the offset range. */ /* byte aligned destination (long + 1) */ .align 2 .loop_do1r: mov.l @r6,r1 /* load first long */ add #-8,r6 /* decrement source addr */ mov.l @(12,r6),r0 /* load second long */ cmp/hi r3,r6 /* runs r6 down to first or second long bound */ mov.b r0,@-r4 /* store low byte of second long */ shlr8 r0 /* get upper 3 bytes */ mov r1,r2 /* copy first long */ shll16 r2 /* move low byte of first long all the way up, .. */ shll8 r2 or r2,r0 /* ..combine with the 3 bytes of second long.. */ mov.l r0,@-r4 /* ..and store as long */ shlr8 r1 /* get middle 2 bytes */ mov.w r1,@-r4 /* store as word */ shlr16 r1 /* get upper byte */ mov.b r1,@-r4 /* and store */ bt .loop_do1r add #-4,r3 /* readjust end address */ .last_do13r: cmp/hi r3,r6 /* first long left? */ bf .start_b2r /* no, jump to trailing byte loop */ nop /* alignment */ mov.l @(4,r6),r0 /* load first long */ add #-4,r6 /* decrement source addr */ mov.b r0,@-r4 /* store low byte */ shlr8 r0 /* get middle 2 bytes */ mov.w r0,@-r4 /* store as word */ shlr16 r0 /* get upper byte */ bra .start_b2r /* jump to trailing byte loop */ mov.b r0,@-r4 /* and store */ /* byte aligned destination (long + 3) */ .align 2 .loop_do3r: mov.l @r6,r1 /* load first long */ add #-8,r6 /* decrement source addr */ mov.l @(12,r6),r0 /* load second long */ mov r1,r2 /* copy first long */ mov.b r0,@-r4 /* store low byte of second long */ shlr8 r0 /* get middle 2 bytes */ mov.w r0,@-r4 /* store as word */ shlr16 r0 /* get upper byte */ shll8 r2 /* move lower 3 bytes of first long one up.. */ or r2,r0 /* ..combine with the 1 byte of second long.. */ mov.l r0,@-r4 /* ..and store as long */ shlr16 r1 /* get upper byte of first long */ shlr8 r1 cmp/hi r3,r6 /* runs r6 down to first or second long bound */ mov.b r1,@-r4 /* ..and store */ bt .loop_do3r bra .last_do13r /* handle first longword: reuse routine for (long + 1) */ add #-4,r3 /* readjust end address */ /* trailing byte loop: copies 0..3 bytes (or all for < 11 in total) */ .align 2 .loop_b2r: mov.b @(7,r6),r0 /* load byte */ add #-1,r6 /* decrement source addr */ mov.b r0,@-r4 /* store byte */ .start_b2r: cmp/hi r5,r6 /* runs r6 down to start address */ bt .loop_b2r rts mov r4,r0 /* return dest start address */ .end: .size _memmove,.end-_memmove