9dd460a47f
This bootloader right now just prints the letter A, but should be capable of reading blocks from the SD card into memory.
23 lines
400 B
ArmAsm
23 lines
400 B
ArmAsm
.export _sd_readblock
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.autoimport
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.importzp sreg
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; sreg is the pointer to store the data
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; a/y is the block address
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; send command 17 with the block address of 00/y/a
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; void sd_readblock(uint16_t addr, void* buf);
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_sd_readblock:
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sta sreg ; move buf pointer to sreg
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stx sreg+1
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jsr popax ; move addr to a/y
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tya
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ldx #$1 ; call interrupt 1
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brk
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rts |