109 lines
2.7 KiB
ArmAsm
109 lines
2.7 KiB
ArmAsm
.importzp sp, ptr1, ptr2, ptr3, ptr4, tmp1, tmp2, tmp3, sreg, data_start
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.autoimport on
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.export fatbuf
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.feature string_escapes
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.MACPACK generic
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fatbuf = $A000
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.segment "BOOTLOADER"
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sectors_per_cluster = $800D
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reserved_sectors = $800E
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fat_count = $8010
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sectors_per_fat = $8024
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_start:
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lda #<str
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ldx #>str
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jsr _cputs
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; Read root directory entry into fatbuf
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lda data_start
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ldx data_start + 1
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jsr pushax
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stz sreg
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stz sreg+1
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jsr pusheax
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lda #<fatbuf
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ldx #>fatbuf
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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 #<fatbuf
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ldx #>fatbuf
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jsr _SD_printBuf
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lda #$20 ; Start at first directory entry (first is a disk label)
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sta ptr3
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lda #>fatbuf
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sta ptr3 + 1
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ldy #$0b ; look for attributes
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@1: lda (ptr3),y
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cmp #$0f ; if attribute is 0xf, this is a lfn
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bne @2 ; if not an lfn, then try to read filename
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@next: clc ; otherwise, go to the next entry (+0x20)
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lda ptr3
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adc #$20
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sta ptr3
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lda #<word_str
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ldx #>word_str
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jsr pushax
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lda ptr3
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ldx ptr3 + 1
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pha
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phx
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jsr pushax
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phy
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ldy #$4
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jsr _cprintf
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ply
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plx
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stx ptr3 + 1
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pla
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sta ptr3
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bra @1
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@2: ldy #11 ; ignore the attributes. Write null to make a string
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lda #$00
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sta (ptr3),y
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lda ptr3 ; store address of the filename string on the stack
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pha
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ldx ptr3 + 1
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phx
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; jsr _cputs ; print out short filenames as we read them
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lda #<kernel_str ; load the string "KERNEL O65"
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ldx #>kernel_str
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jsr pushax
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plx ; then push the string we read earlier
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pla
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jsr _strcmp
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bne @next ; if they are not equal then try next entry
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lda #<_good ; print match if we found it
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ldx #>_good
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jsr _cputs ; otherwise continue on
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@3: jmp @3
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; parse root directory for kernel.o65
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; load first data cluster (we know this is root.)
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; If kernel is not in this then we can go read the FAT
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; later. Saves time if kernel is near beginning
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; bootsector should still be loaded at $8000
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; data start should still be valid
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str: .asciiz "boot2\r\n"
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kernel_str: .asciiz "KERNEL O65"
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_good: .asciiz "Found KERNEL"
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word_str: .asciiz "Word Value: %x\r\n" |