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Find bootloader in FAT

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This commit is contained in:
Byron Lathi
2023-08-12 19:03:24 -07:00
parent fd9389268a
commit 053b0d7e3e
6 changed files with 111 additions and 126 deletions
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2
sw/bios/Makefile
View File

@@ -21,7 +21,7 @@ all: $(HEX)
$(HEX): $(BIN)
objcopy --input-target=binary --output-target=verilog $(BIN) $(HEX)
diff $(HEX) $(FPGA_IMG)
cmp $(HEX) $(FPGA_IMG)
$(BIN): $(OBJS)

127
sw/bios/bootloader.s
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@@ -34,70 +34,6 @@ _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
pla
clc
adc #<addrl
ldx #>addrl
jsr pusheax
lda #<buf
ldx #>buf
jsr pushax
lda #<ptr1
ldx #>ptr1
jsr _SD_readSingleBlock
lda #<buf
ldx #>buf
jsr _SD_printBuf
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
@@ -120,16 +56,63 @@ _main:
jsr _SD_printBuf
lda #$20
sta ptr2
lda #$82
sta ptr2 + 1
ldy #$0b
@1: lda (ptr2),y
cmp #$0f
bne @2
clc
lda ptr2
adc #$20
sta ptr2
bra @1
@2: lda #$00
sta (ptr2),y
lda #<entry
ldx #>entry
jsr _cputs
lda #<name
ldx #>name
jsr pushax
clc
tya
adc ptr2
pha
ldx ptr2 + 1
phx
jsr pushax
ldy #$4
jsr _cprintf
lda #<_boot2_str
ldx #>_boot2_str
jsr pushax
plx
pla
jsr _strcmp
bne @fail
lda #<_good
ldx #>_good
jsr _cputs
bra @end
@fail: lda #<_fail
ldx #>_fail
jsr _cputs
@end: bra @end
_reserved_sect:
.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"
str: .asciiz "boot\r\n"
lfn: .asciiz "Found LFN\r\n"
entry: .asciiz "Found valid entry\r\n"
name: .asciiz "entry name: %s\r\n"
_boot2_str: .asciiz "BOOT2 BIN"
_fail: .asciiz "not bootloader\r\n"
_good: .asciiz "found bootloader!\r\n"
_end:
.res (440+_start-_end)

6
sw/bios/link.ld
View File

@@ -3,7 +3,8 @@ MEMORY
ZP: start = $0, size = $100, type = rw, define = yes;
KERNEL: start = $1000, size = $7000, type = rw, define = yes;
SDRAM: start = $9000, size = $5000, type = rw, define = yes;
BOOTLOADER: start = $8000, size = $1000, type = rw, define = yes, file = "bootloader.bin";
BOOTSECTOR: start = $8000, size = $200, type = rw, define = yes, file = "bootloader.bin";
BOOTLOADER: start = $8200, size = $1000, type = rw, define = yes, file = "boot2.bin";
ROM: start = $F000, size = $1000, file = %O;
}
@@ -17,7 +18,8 @@ SEGMENTS {
CODE: load = ROM, type = ro;
RODATA: load = ROM, type = ro;
VECTORS: load = ROM, type = ro, start = $FFFA;
BOOTSECTOR: load = BOOTLOADER, type = rw, start = $8000;
BOOTSECTOR: load = BOOTSECTOR, type = rw, start = $8000;
BOOTLOADER: load = BOOTLOADER, type = rw;
}
FEATURES {

2
sw/script/format_disk.sh
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@@ -10,7 +10,7 @@ V=-v
STATUS=
echo "$(tput bold setaf 11)Creating Filesystem$(tput sgr 0)"
sudo mkfs.vfat -F32 $DEVICE -n SUPER6502 $V
sudo mkfs.vfat -I -F32 $DEVICE -n SUPER6502 $V
echo
echo "$(tput bold setaf 11)Modifying Boot Sector$(tput sgr 0)"