51 lines
1.2 KiB
ArmAsm
51 lines
1.2 KiB
ArmAsm
.nds
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sdmmc equ 0x434D4453 ;dummy
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.create "emunand.bin", 0x0801A5C0
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.org 0x0801A5C0
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.arm
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nand_sd:
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; Original code that still needs to be executed.
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mov r4, r0
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mov r5, r1
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mov r7, r2
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mov r6, r3
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; End.
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; If we're already trying to access the SD, return.
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ldr r2, [r0, #4]
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ldr r1, =sdmmc
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cmp r2, r1
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beq nand_sd_ret
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str r1, [r0, #4] ; Set object to be SD
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ldr r2, [r0, #8] ; Get sector to read
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cmp r2, #0 ; For GW compatibility, see if we're trying to read the ncsd header (sector 0)
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ldr r3, =nand_offset
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ldr r3, [r3]
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add r2, r3 ; Add the offset to the NAND in the SD.
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ldreq r3, =ncsd_header_offset
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ldreq r3, [r3]
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addeq r2, r3 ; If we're reading the ncsd header, add the offset of that sector.
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str r2, [r0, #8] ; Store sector to read
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nand_sd_ret:
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; Restore registers.
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mov r1, r5
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mov r2, r7
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mov r3, r6
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; Return 4 bytes behind where we got called,
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; due to the offset of this function being stored there.
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mov r0, lr
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add r0, #4
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bx r0
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.pool
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nand_offset: .ascii "NAND" ; for rednand this should be 1
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ncsd_header_offset: .ascii "NCSD" ; depends on nand manufacturer + emunand type (GW/RED)
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.close
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