173 lines
3.1 KiB
ArmAsm
173 lines
3.1 KiB
ArmAsm
.MACPACK generic
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.autoimport
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.feature string_escapes
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.importzp ptr1, sreg
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.import _SD_readSingleBlock
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.export _fat32_init
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.data
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fat_start_sector: .res 2
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data_start_sector: .res 4
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fat_size: .res 4
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sd_buf: .res 512
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bps_val_str: .asciiz "Bytes Per Sector: 0x%x\n"
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sps_val_str: .asciiz "Sectors Per Cluster: 0x%x\n"
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rsv_val_str: .asciiz "Reserved Sectors: 0x%x\n"
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fat_count_str: .asciiz "FAT count: 0x%x\n"
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fat_sect_str: .asciiz "Sectors per FAT: 0x%x\n"
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fat_size_tot_str: .asciiz "Total fat size: 0x%lx\n"
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rsv_sect_bytes_str: .asciiz "Total reserved bytes: 0x%x\n"
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rsv_sd_sectors: .asciiz "Reserved SD Sectors: 0x%x\n"
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data_start_sect_str: .asciiz "Data sector start: 0x%lx\n"
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.code
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bytes_per_sector = sd_buf + $0B
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sectors_per_cluster = sd_buf + $0D
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reserved_sectors = sd_buf + $0E
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fat_count = sd_buf + $10
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sectors_per_fat = sd_buf + $24
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.proc _fat32_init
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; load sector 0 into sd_buf
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lda #$00
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ldx #$00
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stz sreg
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stz sreg+1
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jsr pusheax
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lda #<sd_buf
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ldx #>sd_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 #<bps_val_str
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ldx #>bps_val_str
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jsr pushax
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lda bytes_per_sector
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ldx bytes_per_sector+1
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jsr pushax
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ldy #$4
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jsr _cprintf
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lda #<sps_val_str
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ldx #>sps_val_str
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jsr pushax
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lda sectors_per_cluster
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ldx #$00
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jsr pushax
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ldy #$4
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jsr _cprintf
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lda #<rsv_val_str
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ldx #>rsv_val_str
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jsr pushax
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lda reserved_sectors
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ldx #$00
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jsr pushax
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ldy #$4
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jsr _cprintf
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lda #<fat_count_str
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ldx #>fat_count_str
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jsr pushax
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lda fat_count
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ldx #$00
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jsr pushax
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ldy #$4
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jsr _cprintf
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lda #<rsv_sect_bytes_str
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ldx #>rsv_sect_bytes_str
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jsr pushax
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lda reserved_sectors
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jsr pusha0
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lda bytes_per_sector
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ldx bytes_per_sector+1
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jsr _imulii
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jsr pushax
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phx
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ldy #$4
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jsr _cprintf
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pla
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lsr
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sta fat_start_sector
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stz fat_start_sector + 1
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lda #<fat_size_tot_str
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ldx #>fat_size_tot_str
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jsr pushax
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; multiply fat size and number of fats
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lda fat_count
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jsr pusha0
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lda sectors_per_fat
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ldx sectors_per_fat+1
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jsr _lmulii
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sta fat_size
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stx fat_size+1
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lda sreg
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sta fat_size+2
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lda sreg+1
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sta fat_size+3
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lda fat_size
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ldx fat_size+1
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jsr pusheax
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ldy #$6
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jsr _cprintf
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lda fat_size
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adc fat_start_sector
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sta data_start_sector
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lda fat_size+1
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adc fat_start_sector+1
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sta data_start_sector+1
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lda fat_size+2
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sta data_start_sector+2
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lda fat_size+3
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sta data_start_sector+3
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lda #<data_start_sect_str
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ldx #>data_start_sect_str
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jsr pushax
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lda data_start_sector+2
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sta sreg
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lda data_start_sector+3
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sta sreg+1
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lda data_start_sector
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ldx data_start_sector+1
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jsr pusheax
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ldy #$6
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jsr _cprintf
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; load sector <data_start> into sd_buf
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lda data_start_sector+2
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sta sreg
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lda data_start_sector+3
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sta sreg+1
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lda data_start_sector
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ldx data_start_sector+1
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jsr pusheax
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lda #<sd_buf
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ldx #>sd_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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rts
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.endproc
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