bslathi19/super6502
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Load root directory from sd card

Browse Source
This commit is contained in:
Byron Lathi
2023-08-12 16:09:03 -07:00
parent 7039e649bb
commit fd9389268a
9 changed files with 277 additions and 211 deletions
Download Patch File Download Diff File Expand all files Collapse all files

84
sw/bios/bootloader.s
View File

@@ -13,7 +13,7 @@ _sd_readblock = $6
buf = $8200
addrh = $0000
addrl = $0001
addrl = $0000
.segment "BOOTSECTOR"
@@ -34,11 +34,47 @@ _main:
ldx #>str
jsr _cputs
lda #<_fat_count
ldx #>_fat_count
jsr pushax
lda $8010
ldx #$0
jsr pushax
ldy #$04
jsr _cprintf
; this is offset from bpb?
lda #<_fat_sectors
ldx #>_fat_sectors
jsr pushax
lda $8026
sta sreg
ldx $8027
stx sreg + 1
lda $8024
ldx $8025
jsr pusheax
ldy #$06
jsr _cprintf
lda #<_reserved_sect
ldx #>_reserved_sect
jsr pushax
lda $800E
pha
ldx $800F
jsr pushax
ldy #$04
jsr _cprintf
lda #<addrh
sta sreg
lda #>addrh
sta sreg + 1
lda #<addrl
pla
clc
adc #<addrl
ldx #>addrl
jsr pusheax
lda #<buf
@@ -52,22 +88,48 @@ _main:
ldx #>buf
jsr _SD_printBuf
lda #<_reserved_sect
ldx #>_reserved_sect
jsr pushax
lda $800E
ldx $800F
jsr pushax
ldy #$04
lda #<rd_word
ldx #>rd_word
jsr pushax
lda buf
ldx #$00
jsr pushax
ldy #$4
jsr _cprintf
; we need to read from data segment 0, that will be the first directory entry
; that has sector offset $00ef_e000
lda #$00
sta sreg
lda #$00
sta sreg+1
lda #$f0
ldx #$77
jsr pusheax
lda #<buf
ldx #>buf
jsr pushax
lda #<ptr1
ldx #>ptr1
jsr _SD_readSingleBlock
lda #<buf
ldx #>buf
jsr _SD_printBuf
@end: bra @end
_reserved_sect:
.asciiz "Reserved Sectors: %x\r\n"
.asciiz "Reserved Sectors: %x\r\n"
_fat_sectors:
.asciiz "Sectors per fat: %lx\r\n"
_fat_count:
.asciiz "Fat Count: %x\r\n"
str: .asciiz "Hello from the bootloader!\r\n"
rd_word: .asciiz "Read: %x\r\n"
_end:
.res (440+_start-_end)