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diff --git a/firmware/target/arm/as3525/sansa-clip/lcd-as-clip.S b/firmware/target/arm/as3525/sansa-clip/lcd-as-clip.S
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+/***************************************************************************
+ * __________ __ ___.
+ * Open \______ \ ____ ____ | | _\_ |__ _______ ___
+ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
+ * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
+ * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
+ * \/ \/ \/ \/ \/
+ * $Id$
+ *
+ * Copyright (C) 2008 by Jens Arnold
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#include "as3525.h"
+
+ .text
+ .align 2
+
+ .global lcd_grey_data
+ .type lcd_grey_data,%function
+
+/* A high performance function to write grey phase data to the display,
+ * one or multiple pixels.
+ *
+ * Arguments:
+ * r0 - pixel value data address
+ * r1 - pixel phase data address
+ * r2 - pixel block count
+ *
+ * Register usage:
+ * r3/r4 - current block of phases
+ * r5/r6 - current block of values
+ * r7 - lcd data accumulator
+ * r8 - phase signs mask
+ * lr - lcd bridge address
+ */
+
+lcd_grey_data:
+ stmfd sp!, {r4-r8, lr}
+ mov r8, #0x80
+ orr r8, r8, r8, lsl #8
+ orr r8, r8, r8, lsl #16
+
+ ldr lr, =GPIOA_BASE
+ mov r3, #(1<<5)
+ str r3, [lr, #(4*(1<<5))] @ set pin D/C# of LCD controller (data)
+
+ ldr lr, =DBOP_BASE
+
+.greyloop:
+ ldmia r1, {r3-r4} /* Fetch 8 pixel phases */
+ ldmia r0!, {r5-r6} /* Fetch 8 pixel values */
+
+ mov r7, #0xff
+ tst r3, #0x80
+ biceq r7, r7, #0x80
+ tst r3, #0x8000
+ biceq r7, r7, #0x40
+ tst r3, #0x800000
+ biceq r7, r7, #0x20
+ tst r3, #0x80000000
+ biceq r7, r7, #0x10
+ bic r3, r3, r8
+ add r3, r3, r5
+
+ tst r4, #0x80
+ biceq r7, r7, #0x08
+ tst r4, #0x8000
+ biceq r7, r7, #0x04
+ tst r4, #0x800000
+ biceq r7, r7, #0x02
+ tst r4, #0x80000000
+ biceq r7, r7, #0x01
+ bic r4, r4, r8
+ add r4, r4, r6
+
+ stmia r1!, {r3-r4}
+
+ orr r7, r7, r7, lsl #8 @ we set 15:13 to the MSb and 3:0 to the LSb
+ strh r7, [lr, #0x10] @ DBOP_DOUT
+
+1:
+ ldr r5, [lr, #0xC] @ DBOP_STAT
+ ands r5, r5, #(1<<10) @ wait until push fifo empties
+ beq 1b
+
+ subs r2, r2, #1
+ bne .greyloop
+
+ ldmfd sp!, {r4-r8, pc}
+ .size lcd_grey_data,.-lcd_grey_data