diff options
Diffstat (limited to 'firmware/target/sh/archos/ata-as-archos.S')
| -rwxr-xr-x | firmware/target/sh/archos/ata-as-archos.S | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/firmware/target/sh/archos/ata-as-archos.S b/firmware/target/sh/archos/ata-as-archos.S new file mode 100755 index 0000000000..4a4e7e4b94 --- /dev/null +++ b/firmware/target/sh/archos/ata-as-archos.S @@ -0,0 +1,231 @@ +/*************************************************************************** + * __________ __ ___. + * Open \______ \ ____ ____ | | _\_ |__ _______ ___ + * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / + * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < + * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ + * \/ \/ \/ \/ \/ + * $Id$ + * + * Copyright (C) 2004-2006 by Jens Arnold + * + * All files in this archive are subject to the GNU General Public License. + * See the file COPYING in the source tree root for full license agreement. + * + * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY + * KIND, either express or implied. + * + ****************************************************************************/ + + .section .icode,"ax",@progbits + + .align 2 + .global _copy_read_sectors + .type _copy_read_sectors,@function + +/* Read a number of words from the ATA data port + * + * Assumes wordcount to be a multiple of 4 + * + * Arguments: + * r4 - buffer address + * r5 - word count + * + * Register usage: + * r0 - scratch + * r1/r2 - read buffers + * r3 - mask (if unaligned) + * r4 - current address + * r5 - end address + * r6 - ata port + */ + +_copy_read_sectors: + add r5, r5 /* words -> bytes */ + add r4, r5 /* bytes -> end address */ + add #-12, r5 /* adjust for offsets */ + mov.l .ata_data, r6 + + mov r4, r0 + tst #1, r0 /* 16-bit aligned ? */ + bt .r_aligned /* yes, do word copy */ + + /* not 16-bit aligned */ + mov #-1, r3 /* prepare a bit mask for high byte */ + shll8 r3 /* r3 = 0xFFFFFF00 */ + + mov.w @r6, r2 /* read first word (1st round) */ + mov.b r2, @r4 /* store low byte of first word */ + bra .r_start_b /* jump into loop after next instr. */ + add #-5, r4 /* adjust for dest. offsets; now even */ + + .align 2 +.r_loop_b: /* main loop: copy 4 words in a row */ + mov.w @r6, r2 /* read first word (2+ round) */ + and r3, r1 /* get high byte of fourth word (2+ round) */ + extu.b r2, r0 /* get low byte of first word (2+ round) */ + or r1, r0 /* combine with high byte of fourth word */ + mov.w r0, @(4, r4) /* store at buf[4] */ + nop /* maintain alignment */ +.r_start_b: + mov.w @r6, r1 /* read second word */ + and r3, r2 /* get high byte of first word */ + extu.b r1, r0 /* get low byte of second word */ + or r2, r0 /* combine with high byte of first word */ + mov.w r0, @(6, r4) /* store at buf[6] */ + add #8, r4 /* buf += 8 */ + mov.w @r6, r2 /* read third word */ + and r3, r1 /* get high byte of second word */ + extu.b r2, r0 /* get low byte of third word */ + or r1, r0 /* combine with high byte of second word */ + mov.w r0, @r4 /* store at buf[0] */ + cmp/hi r4, r5 /* check for end */ + mov.w @r6, r1 /* read fourth word */ + and r3, r2 /* get high byte of third word */ + extu.b r1, r0 /* get low byte of fourth word */ + or r2, r0 /* combine with high byte of third word */ + mov.w r0, @(2, r4) /* store at buf[2] */ + bt .r_loop_b + /* 24 instructions for 4 copies, takes 30 clock cycles (4 wait) */ + /* avg. 7.5 cycles per word */ + + swap.b r1, r0 /* get high byte of last word */ + rts + mov.b r0, @(4, r4) /* and store it */ + + /* 16-bit aligned, loop(read and store word) */ +.r_aligned: + mov.w @r6, r2 /* read first word (1st round) */ + bra .r_start_w /* jump into loop after next instr. */ + add #-6, r4 /* adjust for destination offsets */ + + .align 2 +.r_loop_w: /* main loop: copy 4 words in a row */ + mov.w @r6, r2 /* read first word (2+ round) */ + swap.b r1, r0 /* swap fourth word (2+ round) */ + mov.w r0, @(4, r4) /* store fourth word (2+ round) */ + nop /* maintain alignment */ +.r_start_w: + mov.w @r6, r1 /* read second word */ + swap.b r2, r0 /* swap first word */ + mov.w r0, @(6, r4) /* store first word in buf[6] */ + add #8, r4 /* buf += 8 */ + mov.w @r6, r2 /* read third word */ + swap.b r1, r0 /* swap second word */ + mov.w r0, @r4 /* store second word in buf[0] */ + cmp/hi r4, r5 /* check for end */ + mov.w @r6, r1 /* read fourth word */ + swap.b r2, r0 /* swap third word */ + mov.w r0, @(2, r4) /* store third word */ + bt .r_loop_w + /* 16 instructions for 4 copies, takes 22 clock cycles (4 wait) */ + /* avg. 5.5 cycles per word */ + + swap.b r1, r0 /* swap fourth word (last round) */ + rts + mov.w r0, @(4, r4) /* and store it */ + +.r_end: + .size _copy_read_sectors,.r_end-_copy_read_sectors + + .align 2 + .global _copy_write_sectors + .type _copy_write_sectors,@function + +/* Write a number of words to the ATA data port + * + * Assumes wordcount to be a multiple of 2. + * Writing is not unrolled as much as reading, for several reasons: + * + * - a similar instruction sequence is faster for writing than for reading + * because the auto-incrementing load inctructions can be used + * - writing profits from warp mode + * + * Both of these add up to have writing faster than the more unrolled reading. + * + * Arguments: + * r4 - buffer address + * r5 - word count + * + * Register usage: + * r0/r1 - scratch + * r2/r3 - write buffers + * r4 - current address + * r5 - end address + * r6 - mask (if unaligned) + * r7 - ata port + */ + +_copy_write_sectors: + add r5, r5 /* words -> bytes */ + add r4, r5 /* bytes -> end address */ + add #-4, r5 /* adjust for offsets */ + mov.l .ata_data, r7 + + mov r4, r0 + tst #1, r0 /* 16-bit aligned ? */ + bt .w_aligned /* yes, do word copy */ + + /* not 16-bit aligned */ + mov #-1, r6 /* prepare a bit mask for high byte */ + shll8 r6 /* r6 = 0xFFFFFF00 */ + + mov.b @r4+, r2 /* load (initial old second) first byte */ + mov.w @r4+, r3 /* load (initial) first word */ + bra .w_start_b + extu.b r2, r0 /* extend unsigned */ + + .align 2 +.w_loop_b: /* main loop: copy 2 words in a row */ + mov.w @r4+, r3 /* load first word (2+ round) */ + extu.b r2, r0 /* put away low byte of second word (2+ round) */ + and r6, r2 /* get high byte of second word (2+ round) */ + or r1, r2 /* combine with low byte of old first word */ + mov.w r2, @r7 /* write that */ +.w_start_b: + cmp/hi r4, r5 /* check for end */ + mov.w @r4+, r2 /* load second word */ + extu.b r3, r1 /* put away low byte of first word */ + and r6, r3 /* get high byte of first word */ + or r0, r3 /* combine with high byte of old second word */ + mov.w r3, @r7 /* write that */ + bt .w_loop_b + /* 12 instructions for 2 copies, takes 14 clock cycles */ + /* avg. 7 cycles per word */ + + /* the loop "overreads" 1 byte past the buffer end, however, the last */ + /* byte is not written to disk */ + and r6, r2 /* get high byte of last word */ + or r1, r2 /* combine with low byte of old first word */ + rts + mov.w r2, @r7 /* write last word */ + + /* 16-bit aligned, loop(load and write word) */ +.w_aligned: + bra .w_start_w /* jump into loop after next instr. */ + mov.w @r4+, r2 /* load first word (1st round) */ + + .align 2 +.w_loop_w: /* main loop: copy 2 words in a row */ + mov.w @r4+, r2 /* load first word (2+ round) */ + swap.b r1, r0 /* swap second word (2+ round) */ + mov.w r0, @r7 /* write second word (2+ round) */ +.w_start_w: + cmp/hi r4, r5 /* check for end */ + mov.w @r4+, r1 /* load second word */ + swap.b r2, r0 /* swap first word */ + mov.w r0, @r7 /* write first word */ + bt .w_loop_w + /* 8 instructions for 2 copies, takes 10 clock cycles */ + /* avg. 5 cycles per word */ + + swap.b r1, r0 /* swap second word (last round) */ + rts + mov.w r0, @r7 /* and write it */ + +.w_end: + .size _copy_write_sectors,.w_end-_copy_write_sectors + + .align 2 +.ata_data: + .long 0x06104100 /* ATA data port */ |