1/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 *  linux/arch/arm/lib/ll_char_wr.S
  4 *
  5 *  Copyright (C) 1995, 1996 Russell King.
  6 *
  7 *  Speedups & 1bpp code (C) 1996 Philip Blundell & Russell King.
  8 *
  9 *  10-04-96	RMK	Various cleanups & reduced register usage.
 10 *  08-04-98	RMK	Shifts re-ordered
 11 */
 12
 13@ Regs: [] = corruptible
 14@       {} = used
 15@       () = do not use
 16
 17#include <linux/linkage.h>
 18#include <asm/assembler.h>
 19	.text
 20
 21LC0:	.word	LC0
 22	.word	bytes_per_char_h
 23	.word	video_size_row
 24	.word	acorndata_8x8
 25	.word	con_charconvtable
 26
 27/*
 28 * r0 = ptr
 29 * r1 = char
 30 * r2 = white
 31 */
 32ENTRY(ll_write_char)
 33	stmfd	sp!, {r4 - r7, lr}
 34@
 35@ Smashable regs: {r0 - r3}, [r4 - r7], (r8 - fp), [ip], (sp), [lr], (pc)
 36@
 37	/*
 38	 * calculate offset into character table
 39	 */
 40	mov	r1, r1, lsl #3
 41	/*
 42	 * calculate offset required for each row.
 43	 */
 44	adr	ip, LC0
 45	ldmia	ip, {r3, r4, r5, r6, lr}
 46	sub	ip, ip, r3
 47	add	r6, r6, ip
 48	add	lr, lr, ip
 49	ldr	r4, [r4, ip]
 50	ldr	r5, [r5, ip]
 51	/*
 52	 * Go to resolution-dependent routine...
 53	 */
 54	cmp	r4, #4
 55	blt	Lrow1bpp
 56	add	r0, r0, r5, lsl #3		@ Move to bottom of character
 57	orr	r1, r1, #7
 58	ldrb	r7, [r6, r1]
 59	teq	r4, #8
 60	beq	Lrow8bpplp
 61@
 62@ Smashable regs: {r0 - r3}, [r4], {r5 - r7}, (r8 - fp), [ip], (sp), {lr}, (pc)
 63@
 64Lrow4bpplp:
 65	ldr	r7, [lr, r7, lsl #2]
 66	mul	r7, r2, r7
 67	sub	r1, r1, #1			@ avoid using r7 directly after
 68	str	r7, [r0, -r5]!
 69	ldrb	r7, [r6, r1]
 70	ldr	r7, [lr, r7, lsl #2]
 71	mul	r7, r2, r7
 72	tst	r1, #7				@ avoid using r7 directly after
 73	str	r7, [r0, -r5]!
 74	subne	r1, r1, #1
 75	ldrbne	r7, [r6, r1]
 76	bne	Lrow4bpplp
 77	ldmfd	sp!, {r4 - r7, pc}
 78
 79@
 80@ Smashable regs: {r0 - r3}, [r4], {r5 - r7}, (r8 - fp), [ip], (sp), {lr}, (pc)
 81@
 82Lrow8bpplp:
 83	mov	ip, r7, lsr #4
 84	ldr	ip, [lr, ip, lsl #2]
 85	mul	r4, r2, ip
 86	and	ip, r7, #15			@ avoid r4
 87	ldr	ip, [lr, ip, lsl #2]		@ avoid r4
 88	mul	ip, r2, ip			@ avoid r4
 89	sub	r1, r1, #1			@ avoid ip
 90	sub	r0, r0, r5			@ avoid ip
 91	stmia	r0, {r4, ip}
 92	ldrb	r7, [r6, r1]
 93	mov	ip, r7, lsr #4
 94	ldr	ip, [lr, ip, lsl #2]
 95	mul	r4, r2, ip
 96	and	ip, r7, #15			@ avoid r4
 97	ldr	ip, [lr, ip, lsl #2]		@ avoid r4
 98	mul	ip, r2, ip			@ avoid r4
 99	tst	r1, #7				@ avoid ip
100	sub	r0, r0, r5			@ avoid ip
101	stmia	r0, {r4, ip}
102	subne	r1, r1, #1
103	ldrbne	r7, [r6, r1]
104	bne	Lrow8bpplp
105	ldmfd	sp!, {r4 - r7, pc}
106
107@
108@ Smashable regs: {r0 - r3}, [r4], {r5, r6}, [r7], (r8 - fp), [ip], (sp), [lr], (pc)
109@
110Lrow1bpp:
111	add	r6, r6, r1
112	ldmia	r6, {r4, r7}
113	strb	r4, [r0], r5
114	mov	r4, r4, lsr #8
115	strb	r4, [r0], r5
116	mov	r4, r4, lsr #8
117	strb	r4, [r0], r5
118	mov	r4, r4, lsr #8
119	strb	r4, [r0], r5
120	strb	r7, [r0], r5
121	mov	r7, r7, lsr #8
122	strb	r7, [r0], r5
123	mov	r7, r7, lsr #8
124	strb	r7, [r0], r5
125	mov	r7, r7, lsr #8
126	strb	r7, [r0], r5
127	ldmfd	sp!, {r4 - r7, pc}
128
129	.bss
130ENTRY(con_charconvtable)
131	.space	1024