mirror of
https://github.com/RaySollium99/picodrive.git
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1cfc5cc4ce
git-svn-id: file:///home/notaz/opt/svn/PicoDrive@576 be3aeb3a-fb24-0410-a615-afba39da0efa
76 lines
1.7 KiB
ArmAsm
76 lines
1.7 KiB
ArmAsm
@ vim:filetype=armasm
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@ Memory converters for different modes
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@ (c) Copyright 2007, Grazvydas "notaz" Ignotas
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@ r10 is tmp, io1 is lsb halfword, io2 is msb
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@ | 0 1 | 2 3 | -> | 0 2 | 1 3 | (little endian)
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.macro _conv_reg io1 io2
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mov r10, \io2, lsl #16
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and \io2, \io2, r11, lsl #16
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orr \io2, \io2, \io1, lsr #16
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and \io1, \io1, r11
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orr \io1, \io1, r10
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/*
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mov \io2, \io2, ror #16
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mov r10, \io1, lsl #16
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orr r10, r10, \io2, lsr #16
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mov \io1, \io1, lsr #16
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orr \io1, \io1, \io2, lsl #16
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mov \io2, r10, ror #16
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*/
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.endm
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.global wram_2M_to_1M
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wram_2M_to_1M:
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stmfd sp!,{r4-r11,lr}
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add r1, r0, #0x60000 @ m1M_b1
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add r0, r0, #0x40000 @ m1M_b0
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mov r2, r0 @ m2M
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mov r11, #0xff
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orr r11, r11, r11, lsl #8
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mov r12, #(0x40000/8/4)
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_2Mto1M_loop:
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ldmdb r2!,{r3-r9,lr}
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_conv_reg r3,r4
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_conv_reg r5,r6
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_conv_reg r7,r8
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_conv_reg r9,lr
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subs r12, r12, #1
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stmdb r0!,{r3,r5,r7,r9}
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stmdb r1!,{r4,r6,r8,lr}
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bne _2Mto1M_loop
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ldmfd sp!,{r4-r11,pc}
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.global wram_1M_to_2M
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wram_1M_to_2M:
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stmfd sp!,{r4-r11,lr}
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mov r2, r0 @ m2M
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add r1, r0, #0x40000 @ m1M_b1
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add r0, r0, #0x20000 @ m1M_b0
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mov r11, #0xff
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orr r11, r11, r11, lsl #8
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mov r12, #(0x40000/8/4)
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_1Mto2M_loop:
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ldmia r0!,{r3,r5,r7,r9}
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ldmia r1!,{r4,r6,r8,lr}
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_conv_reg r3,r4
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_conv_reg r5,r6
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_conv_reg r7,r8
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_conv_reg r9,lr
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subs r12, r12, #1
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stmia r2!,{r3-r9,lr}
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bne _1Mto2M_loop
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ldmfd sp!,{r4-r11,pc}
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