069ae5db4b
I think there may still be some issues with a drive that is formatted wrong, but it works consistently right now. When modifying the boot sector, it now leaves alone the partition tables and the bios parameter block. This does reduce the amount of code from 510 bytes to 380, but this is find as it only takes about 29 bytes to load a sector into memory.
73 lines
959 B
ArmAsm
73 lines
959 B
ArmAsm
.importzp sp, ptr1, ptr2, ptr3, ptr4, tmp1, tmp2, tmp3, sreg
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.autoimport on
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.feature string_escapes
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.MACPACK generic
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_console_clear = $0
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_console_read_char = $2
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_console_write_char = $4
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_sd_readblock = $6
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buf = $8200
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addrh = $0000
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addrl = $0001
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.segment "BOOTSECTOR"
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_start:
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jmp _main
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.byte "SUPR6502"
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_preamble:
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.res (11+_start-_preamble)
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_bpb: .res 60
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_main:
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lda #<str
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ldx #>str
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jsr _cputs
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lda #<addrh
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sta sreg
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lda #>addrh
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sta sreg + 1
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lda #<addrl
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ldx #>addrl
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jsr pusheax
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lda #<buf
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ldx #>buf
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jsr pushax
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lda #<ptr1
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ldx #>ptr1
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jsr _SD_readSingleBlock
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lda #<buf
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ldx #>buf
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jsr _SD_printBuf
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@end: bra @end
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str: .asciiz "Hello from the bootloader!\r\n"
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_end:
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.res (440+_start-_end)
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.res 6
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.res 16
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.res 16
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.res 16
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.res 16
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.byte $55
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.byte $AA
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