mirror of
https://github.com/LNH-team/pico-loader.git
synced 2026-06-02 09:16:49 +02:00
106 lines
2.7 KiB
ArmAsm
106 lines
2.7 KiB
ArmAsm
#include "asminc.h"
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.syntax unified
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.thumb
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.section "datel_read", "ax"
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.global datel_readSectorSdhcLabel
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@ All the called functions leave every registers unchanged, except for r0 in case the function has a return value
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@datel_SDReadMultipleSector(u32 sector, u8 * buffer, u32 num_sectors)
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BEGIN_ASM_FUNC datel_SDReadMultipleSector
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push {r3-r7, lr}
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movs r4, r1
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@ We get the number of bytes total to write, which we'll compare to against in the main loop
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lsls r3, r2, #9
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@ Total written bytes
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movs r5, #0
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datel_readSectorSdhcLabel:
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@ if not sdhc this needs to be shifted to the left by 9
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lsls r0, #9
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@mov r0, r0
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movs r1, DATEL_SDIO_CMD18_READ_MULTIPLE_BLOCK
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ldr r7, datel_SDReadMultipleSector_SpiSendSDIOCommandR0
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bl datel_SDReadMultipleSector_Interwork
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bne CMD18_not_ok
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read_next_sector:
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ldr r7, datel_SDReadMultipleSector_ReadSpiByteTimeout
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bl datel_SDReadMultipleSector_Interwork
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cmp r0, DATEL_SPI_START_DATA_TOKEN
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bne wrong_spi_start_token
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@ preload datel_readSpiShort
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ldr r7, datel_SDReadMultipleSector_ReadSpiShort
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read_next_byte:
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bl datel_SDReadMultipleSector_Interwork
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strh r0, [r4, r5]
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adds r5, #2
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@ Shifting left by 0x17 will set the Zero flag if the number that was shifted is a multiple
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@ of 0x200 (indicating a full sector has been written)
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lsls r0, r5, #0x17
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bne read_next_byte
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@ drop crc
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bl datel_SDReadMultipleSector_Interwork
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cmp r3, r5
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bne read_next_sector
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movs r0, #0
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movs r1, DATEL_SDIO_CMD12_STOP_TRANSMISSION
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movs r2, #7
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@ datel_spiSendSDIOCommand is 1 instruction after datel_spiSendSDIOCommandR0
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ldr r7, datel_SDReadMultipleSector_SpiSendSDIOCommandR0
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adds r7, #2
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bl datel_SDReadMultipleSector_Interwork
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@ use a timeout of 0x1000 instead of 0xFFF, easier to setup, then halve it
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@ since we're reading 2 bytes at the time
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@ ldr r4, =DATEL_SD_CMD_TIMEOUT_LEN
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movs r4, #1
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lsls r4, #11
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ldr r7, datel_SDReadMultipleSector_ReadSpiShort
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1:
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bl datel_SDReadMultipleSector_Interwork
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bne read_timeout_expired
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subs r4, #1
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bne 1b
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read_timeout_expired:
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@ movs r0, r4
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@ subs r3, r0, #1
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@ sbcs r0, r3
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@ pico loader has no error result
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@ pop {r3-r7, pc}
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CMD18_not_ok:
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wrong_spi_start_token:
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@ movs r0, #0
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pop {r3-r7, pc}
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datel_SDReadMultipleSector_Interwork:
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bx r7
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.balign 4
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.pool
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.global datel_SDReadMultipleSector_SpiSendSDIOCommandR0
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datel_SDReadMultipleSector_SpiSendSDIOCommandR0:
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.word 0
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.global datel_SDReadMultipleSector_ReadSpiByteTimeout
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datel_SDReadMultipleSector_ReadSpiByteTimeout:
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.word 0
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.global datel_SDReadMultipleSector_ReadSpiShort
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datel_SDReadMultipleSector_ReadSpiShort:
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.word 0
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