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
21 LC0: .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 */
32 ENTRY(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 @
64 Lrow4bpplp:
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 @
82 Lrow8bpplp:
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 @
110 Lrow1bpp:
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
130 ENTRY(con_charconvtable)
131 .space 1024
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