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-rw-r--r--arch/arm/boot/compressed/ll_char_wr.S131
1 files changed, 131 insertions, 0 deletions
diff --git a/arch/arm/boot/compressed/ll_char_wr.S b/arch/arm/boot/compressed/ll_char_wr.S
new file mode 100644
index 000000000..1ec8cb289
--- /dev/null
+++ b/arch/arm/boot/compressed/ll_char_wr.S
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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