Files
pico-loader/arm9/source/patches/platform/g003/g003ReadSdDmaAsm.s
2025-11-23 17:14:17 +01:00

101 lines
2.0 KiB
ArmAsm

.cpu arm946e-s
.section "g003_readsddma", "ax"
.syntax unified
.thumb
// r0 = src sector
// r1 = previous src sector
// r2 = dma channel
// r3 = dst
.global g003_readSdDma
.type g003_readSdDma, %function
g003_readSdDma:
push {r4-r7,lr}
ldr r4, =0x040001A0
movs r7, #0x80
strb r7, [r4,#0x1]
sector_loop:
// request sd read for sector, sector << 1 == 0xaabbccdd
// C9 bb cc dd 00 00 00 aa
// left shift sector address 1
lsls r0, r0, #1
movs r7, #0xC9
strb r7, [r4,#0x8]
lsrs r7, r0, #24
strb r7, [r4,#0xF] // place MSByte of sector address at end of command instead
lsrs r7, r0, #16
strb r7, [r4,#0x9]
lsrs r7, r0, #8
strb r7, [r4,#0xA]
lsls r7, r0, #24
lsrs r7, r7, #24 // r7 = dd
// Ace3DS+ code uses str, but G003 doesn't store the last byte at u8 MCCMD1[4].
// So we use strb just like the other bytes.
strb r7, [r4,#0xB]
ldr r1, =0x04100010
C9_poll_loop:
ldr r7, =0xA7586000
str r7, [r4,#0x4]
C9_poll_transfer_loop:
ldrb r7, [r4,#0x6]
lsrs r7, r7, #8
bcc C9_poll_check_transfer_end
ldr r5, [r1]
C9_poll_check_transfer_end:
ldrb r7, [r4,#0x7]
lsrs r7, r7, #8
bcs C9_poll_transfer_loop
cmp r5, #0
bne C9_poll_loop
// Setup data read card command
movs r7, #0xCA
str r7, [r4,#0x8]
str r5, [r4,#0xC] // r5 is 0 here
readDataWithDma:
movs r0, r2 // DMA channel
movs r2, r3 // Destination
movs r3, #1
lsls r3, r3, #9 // (1 << 9) = 512 = count
ldr r6, g003_readSdDma_miiCardDmaCopy32Ptr
blx r6
CA_data_dma:
movs r7, #0xC0 // select rom mode, with irq
strb r7, [r4,#0x1]
ldr r7, =0xA1586000
str r7, [r4,#0x4]
pop {r4-r7,pc}
.balign 4
.global g003_readSdDma_miiCardDmaCopy32Ptr
g003_readSdDma_miiCardDmaCopy32Ptr:
.word 0
.pool
.global g003_finishReadSdDma
.type g003_finishReadSdDma, %function
g003_finishReadSdDma:
// No cleanup needed on this platform.
bx lr
.balign 4
.pool
.end