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| /* SPDX-License-Identifier: GPL-2.0-only */
| /*
| * linux/arch/arm/lib/ll_char_wr.S
| *
| * Copyright (C) 1995, 1996 Russell King.
| *
| * Speedups & 1bpp code (C) 1996 Philip Blundell & Russell King.
| *
| * 10-04-96 RMK Various cleanups & reduced register usage.
| * 08-04-98 RMK Shifts re-ordered
| */
|
| @ Regs: [] = corruptible
| @ {} = used
| @ () = do not use
|
| #include <linux/linkage.h>
| #include <asm/assembler.h>
| .text
|
| LC0: .word LC0
| .word bytes_per_char_h
| .word video_size_row
| .word acorndata_8x8
| .word con_charconvtable
|
| /*
| * r0 = ptr
| * r1 = char
| * r2 = white
| */
| ENTRY(ll_write_char)
| stmfd sp!, {r4 - r7, lr}
| @
| @ Smashable regs: {r0 - r3}, [r4 - r7], (r8 - fp), [ip], (sp), [lr], (pc)
| @
| /*
| * calculate offset into character table
| */
| mov r1, r1, lsl #3
| /*
| * calculate offset required for each row.
| */
| adr ip, LC0
| ldmia ip, {r3, r4, r5, r6, lr}
| sub ip, ip, r3
| add r6, r6, ip
| add lr, lr, ip
| ldr r4, [r4, ip]
| ldr r5, [r5, ip]
| /*
| * Go to resolution-dependent routine...
| */
| cmp r4, #4
| blt Lrow1bpp
| add r0, r0, r5, lsl #3 @ Move to bottom of character
| orr r1, r1, #7
| ldrb r7, [r6, r1]
| teq r4, #8
| beq Lrow8bpplp
| @
| @ Smashable regs: {r0 - r3}, [r4], {r5 - r7}, (r8 - fp), [ip], (sp), {lr}, (pc)
| @
| Lrow4bpplp:
| ldr r7, [lr, r7, lsl #2]
| mul r7, r2, r7
| sub r1, r1, #1 @ avoid using r7 directly after
| str r7, [r0, -r5]!
| ldrb r7, [r6, r1]
| ldr r7, [lr, r7, lsl #2]
| mul r7, r2, r7
| tst r1, #7 @ avoid using r7 directly after
| str r7, [r0, -r5]!
| subne r1, r1, #1
| ldrbne r7, [r6, r1]
| bne Lrow4bpplp
| ldmfd sp!, {r4 - r7, pc}
|
| @
| @ Smashable regs: {r0 - r3}, [r4], {r5 - r7}, (r8 - fp), [ip], (sp), {lr}, (pc)
| @
| Lrow8bpplp:
| mov ip, r7, lsr #4
| ldr ip, [lr, ip, lsl #2]
| mul r4, r2, ip
| and ip, r7, #15 @ avoid r4
| ldr ip, [lr, ip, lsl #2] @ avoid r4
| mul ip, r2, ip @ avoid r4
| sub r1, r1, #1 @ avoid ip
| sub r0, r0, r5 @ avoid ip
| stmia r0, {r4, ip}
| ldrb r7, [r6, r1]
| mov ip, r7, lsr #4
| ldr ip, [lr, ip, lsl #2]
| mul r4, r2, ip
| and ip, r7, #15 @ avoid r4
| ldr ip, [lr, ip, lsl #2] @ avoid r4
| mul ip, r2, ip @ avoid r4
| tst r1, #7 @ avoid ip
| sub r0, r0, r5 @ avoid ip
| stmia r0, {r4, ip}
| subne r1, r1, #1
| ldrbne r7, [r6, r1]
| bne Lrow8bpplp
| ldmfd sp!, {r4 - r7, pc}
|
| @
| @ Smashable regs: {r0 - r3}, [r4], {r5, r6}, [r7], (r8 - fp), [ip], (sp), [lr], (pc)
| @
| Lrow1bpp:
| add r6, r6, r1
| ldmia r6, {r4, r7}
| strb r4, [r0], r5
| mov r4, r4, lsr #8
| strb r4, [r0], r5
| mov r4, r4, lsr #8
| strb r4, [r0], r5
| mov r4, r4, lsr #8
| strb r4, [r0], r5
| strb r7, [r0], r5
| mov r7, r7, lsr #8
| strb r7, [r0], r5
| mov r7, r7, lsr #8
| strb r7, [r0], r5
| mov r7, r7, lsr #8
| strb r7, [r0], r5
| ldmfd sp!, {r4 - r7, pc}
|
| .bss
| ENTRY(con_charconvtable)
| .space 1024
|
|
