LXR linux/arch/arm/boot/compressed/ll_char

   1/*
   2 *  linux/arch/arm/lib/ll_char_wr.S
   3 *
   4 *  Copyright (C) 1995, 1996 Russell King.
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License version 2 as
   8 * published by the Free Software Foundation.
   9 *
  10 *  Speedups & 1bpp code (C) 1996 Philip Blundell & Russell King.
  11 *
  12 *  10-04-96    RMK     Various cleanups & reduced register usage.
  13 *  08-04-98    RMK     Shifts re-ordered
  14 */
  15
  16@ Regs: [] = corruptible
  17@       {} = used
  18@       () = do not use
  19
  20#include <linux/linkage.h>
  21#include <asm/assembler.h>
  22        .text
  23
  24LC0:    .word   LC0
  25        .word   bytes_per_char_h
  26        .word   video_size_row
  27        .word   acorndata_8x8
  28        .word   con_charconvtable
  29
  30/*
  31 * r0 = ptr
  32 * r1 = char
  33 * r2 = white
  34 */
  35ENTRY(ll_write_char)
  36        stmfd   sp!, {r4 - r7, lr}
  37@
  38@ Smashable regs: {r0 - r3}, [r4 - r7], (r8 - fp), [ip], (sp), [lr], (pc)
  39@
  40        /*
  41         * calculate offset into character table
  42         */
  43        mov     r1, r1, lsl #3
  44        /*
  45         * calculate offset required for each row.
  46         */
  47        adr     ip, LC0
  48        ldmia   ip, {r3, r4, r5, r6, lr}
  49        sub     ip, ip, r3
  50        add     r6, r6, ip
  51        add     lr, lr, ip
  52        ldr     r4, [r4, ip]
  53        ldr     r5, [r5, ip]
  54        /*
  55         * Go to resolution-dependent routine...
  56         */
  57        cmp     r4, #4
  58        blt     Lrow1bpp
  59        add     r0, r0, r5, lsl #3              @ Move to bottom of character
  60        orr     r1, r1, #7
  61        ldrb    r7, [r6, r1]
  62        teq     r4, #8
  63        beq     Lrow8bpplp
  64@
  65@ Smashable regs: {r0 - r3}, [r4], {r5 - r7}, (r8 - fp), [ip], (sp), {lr}, (pc)
  66@
  67Lrow4bpplp:
  68        ldr     r7, [lr, r7, lsl #2]
  69        mul     r7, r2, r7
  70        sub     r1, r1, #1                      @ avoid using r7 directly after
  71        str     r7, [r0, -r5]!
  72        ldrb    r7, [r6, r1]
  73        ldr     r7, [lr, r7, lsl #2]
  74        mul     r7, r2, r7
  75        tst     r1, #7                          @ avoid using r7 directly after
  76        str     r7, [r0, -r5]!
  77        subne   r1, r1, #1
  78        ldrneb  r7, [r6, r1]
  79        bne     Lrow4bpplp
  80        ldmfd   sp!, {r4 - r7, pc}
  81
  82@
  83@ Smashable regs: {r0 - r3}, [r4], {r5 - r7}, (r8 - fp), [ip], (sp), {lr}, (pc)
  84@
  85Lrow8bpplp:
  86        mov     ip, r7, lsr #4
  87        ldr     ip, [lr, ip, lsl #2]
  88        mul     r4, r2, ip
  89        and     ip, r7, #15                     @ avoid r4
  90        ldr     ip, [lr, ip, lsl #2]            @ avoid r4
  91        mul     ip, r2, ip                      @ avoid r4
  92        sub     r1, r1, #1                      @ avoid ip
  93        sub     r0, r0, r5                      @ avoid ip
  94        stmia   r0, {r4, ip}
  95        ldrb    r7, [r6, r1]
  96        mov     ip, r7, lsr #4
  97        ldr     ip, [lr, ip, lsl #2]
  98        mul     r4, r2, ip
  99        and     ip, r7, #15                     @ avoid r4
 100        ldr     ip, [lr, ip, lsl #2]            @ avoid r4
 101        mul     ip, r2, ip                      @ avoid r4
 102        tst     r1, #7                          @ avoid ip
 103        sub     r0, r0, r5                      @ avoid ip
 104        stmia   r0, {r4, ip}
 105        subne   r1, r1, #1
 106        ldrneb  r7, [r6, r1]
 107        bne     Lrow8bpplp
 108        ldmfd   sp!, {r4 - r7, pc}
 109
 110@
 111@ Smashable regs: {r0 - r3}, [r4], {r5, r6}, [r7], (r8 - fp), [ip], (sp), [lr], (pc)
 112@
 113Lrow1bpp:
 114        add     r6, r6, r1
 115        ldmia   r6, {r4, r7}
 116        strb    r4, [r0], r5
 117        mov     r4, r4, lsr #8
 118        strb    r4, [r0], r5
 119        mov     r4, r4, lsr #8
 120        strb    r4, [r0], r5
 121        mov     r4, r4, lsr #8
 122        strb    r4, [r0], r5
 123        strb    r7, [r0], r5
 124        mov     r7, r7, lsr #8
 125        strb    r7, [r0], r5
 126        mov     r7, r7, lsr #8
 127        strb    r7, [r0], r5
 128        mov     r7, r7, lsr #8
 129        strb    r7, [r0], r5
 130        ldmfd   sp!, {r4 - r7, pc}
 131
 132        .bss
 133ENTRY(con_charconvtable)
 134        .space  1024
 135