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Add some basic fat32 code

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This commit is contained in:
Byron Lathi
2023-12-03 23:27:45 -08:00
parent 184c58b962
commit 5c74d161d4
11 changed files with 326 additions and 7 deletions
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19
sw/kernel/devices/io.inc65
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@@ -10,4 +10,21 @@ SPI_BAUD = $efd8
SPI_INPUT = $efd9
SPI_OUTPUT = $efda
SPI_CTRL = $efdb
SPI_STATUS = SPI_CTRL
SPI_STATUS = SPI_CTRL
MULTIPLIER_BASE = $eff0
MULTIPLIER_AL = MULTIPLIER_BASE + 0
MULTIPLIER_AH = MULTIPLIER_BASE + 1
MULTIPLIER_BL = MULTIPLIER_BASE + 2
MULTIPLIER_BH = MULTIPLIER_BASE + 3
MULTIPLIER_OLL = MULTIPLIER_BASE + 4
MULTIPLIER_OLH = MULTIPLIER_BASE + 5
MULTIPLIER_OHL = MULTIPLIER_BASE + 6
MULTIPLIER_OHH = MULTIPLIER_BASE + 7
GOLDEN_OUTPUT_0 = $03
GOLDEN_OUTPUT_1 = $0a
GOLDEN_OUTPUT_2 = $08
GOLDEN_OUTPUT_3 = $00

12
sw/kernel/devices/multiplier.h Normal file
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@@ -0,0 +1,12 @@
#ifndef _MULTIPLER_H
#define _MULTIPLER_H
#include <stdint.h>
/* Multiply 2 integers into 1 long */
uint32_t lmulii(uint16_t a, uint16_t b);
/* Multiply 2 integers into 1 integer, discarding upper bits. */
uint16_t imulii(uint16_t a, uint16_t b);
#endif

36
sw/kernel/devices/multiplier.s Normal file
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@@ -0,0 +1,36 @@
.include "io.inc65"
.MACPACK generic
.import popax
.importzp sreg
.export _lmulii, _imulii
.code
.proc _lmulii
sta MULTIPLIER_BL
stx MULTIPLIER_BH
jsr popax
sta MULTIPLIER_AL
stx MULTIPLIER_AH
lda MULTIPLIER_OHL
sta sreg
lda MULTIPLIER_OHH
sta sreg+1
lda MULTIPLIER_OLL
ldx MULTIPLIER_OLH
rts
.endproc
.proc _imulii
sta MULTIPLIER_BL
stx MULTIPLIER_BH
jsr popax
sta MULTIPLIER_AL
stx MULTIPLIER_AH
lda MULTIPLIER_OLL
ldx MULTIPLIER_OLH
rts
.endproc

34
sw/kernel/filesystems/fat32.h Normal file
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@@ -0,0 +1,34 @@
#ifndef _FAT32_H
#define _FAT32_H
#include <stdint.h>
void fat32_init();
struct fat32_directory_entry {
char file_name[8];
char file_ext[3];
uint8_t attr1;
uint8_t create_time_10ms;
uint16_t create_time;
uint16_t create_date;
uint16_t access_date;
uint16_t cluster_high;
uint16_t modified_time;
uint16_t modified_date;
uint16_t cluster_low;
uint32_t file_size;
};
struct lfn_entry {
uint8_t sequence_number;
uint16_t name_0[5];
uint8_t attributes;
uint8_t type;
uint8_t checksum;
uint16_t name_1[6];
uint16_t cluster_low;
uint16_t name_2[2];
};
#endif

115
sw/kernel/filesystems/fat32.s Normal file
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@@ -0,0 +1,115 @@
.MACPACK generic
.autoimport
.feature string_escapes
.importzp ptr1, sreg
.import _SD_readSingleBlock
.export _fat32_init
.data
fat_start_sector: .res 2
data_start_sector: .res 2
sd_buf: .res 512
bps_val_str: .asciiz "Bytes Per Sector: 0x%x\n"
sps_val_str: .asciiz "Sectors Per Cluster: 0x%x\n"
rsv_val_str: .asciiz "Reserved Sectors: 0x%x\n"
fat_count_str: .asciiz "FAT count: 0x%x\n"
fat_sect_str: .asciiz "Sectors per FAT: 0x%x\n"
fat_size_tot_str: .asciiz "Total fat size: 0x%lx\n"
rsv_sect_bytes_str: .asciiz "Total reserved bytes: 0x%x\n"
rsv_sd_sectors: .asciiz "Reserved SD Sectors: 0x%x\n"
.code
bytes_per_sector = sd_buf + $0B
sectors_per_cluster = sd_buf + $0D
reserved_sectors = sd_buf + $0E
fat_count = sd_buf + $10
sectors_per_fat = sd_buf + $24
.proc _fat32_init
; load sector 0 into sd_buf
lda #$00
ldx #$00
stz sreg
stz sreg+1
jsr pusheax
lda #<sd_buf
ldx #>sd_buf
jsr pushax
lda #<ptr1
ldx #>ptr1
jsr _SD_readSingleBlock
lda #<bps_val_str
ldx #>bps_val_str
jsr pushax
lda bytes_per_sector
ldx bytes_per_sector+1
jsr pushax
ldy #$4
jsr _printf
lda #<sps_val_str
ldx #>sps_val_str
jsr pushax
lda sectors_per_cluster
ldx #$00
jsr pushax
ldy #$4
jsr _cprintf
lda #<rsv_val_str
ldx #>rsv_val_str
jsr pushax
lda reserved_sectors
ldx #$00
jsr pushax
ldy #$4
jsr _cprintf
lda #<fat_count_str
ldx #>fat_count_str
jsr pushax
lda fat_count
ldx #$00
jsr pushax
ldy #$4
jsr _cprintf
lda #<rsv_sect_bytes_str
ldx #>rsv_sect_bytes_str
jsr pushax
lda reserved_sectors
jsr pusha0
lda bytes_per_sector
ldx bytes_per_sector+1
jsr _imulii
jsr pushax
ldy #$4
jsr _cprintf
lda #<fat_size_tot_str
ldx #>fat_size_tot_str
jsr pushax
; multiply fat size and number of fats
lda fat_count
jsr pusha0
lda sectors_per_fat
ldx sectors_per_fat+1
jsr _lmulii
jsr pusheax
ldy #$6
jsr _cprintf
rts
.endproc

19
sw/kernel/filesystems/fs.h Normal file
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@@ -0,0 +1,19 @@
#ifndef _FS_H
#define _FS_H
#include <stdint.h>
/* syscalls for files */
int8_t file_read(int8_t fd, void* buf, int8_t nbytes);
int8_t file_write(int8_t fd, const void* buf, int8_t nbytes);
int8_t file_open(const uint8_t* filename);
int8_t file_close(int8_t fd);
/* syscalls for directories */
int8_t directory_read(int8_t fd, void* buf, int8_t nbytes);
int8_t directory_write(int8_t fd, const void* buf, int8_t nbytes);
int8_t directory_open(const uint8_t* filename);
int8_t directory_close(int8_t fd);
#endif

15
sw/kernel/kernel.c
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@@ -6,9 +6,10 @@
#include "devices/mapper.h"
#include "devices/rtc.h"
#include "devices/serial.h"
#include "devices/terminal.h"
#include "filesystems/fat32.h"
void handle_rtc_interrupt() {
// cputs("In IRQ interrupt!\n");
@@ -22,16 +23,16 @@ char buf[128];
int main() {
cputs("Kernel\n");
// cputs("Init Mapper\n");
cputs("Init Mapper\n");
init_mapper();
// cputs("Initialize Interrupts\n");
cputs("Initialize Interrupts\n");
init_interrupts();
// cputs("Initialize Interrupt Controller\n");
cputs("Initialize Interrupt Controller\n");
init_interrupt_controller();
// cputs("Initialize RTC\n");
cputs("Initialize RTC\n");
init_rtc();
register_irq(&handle_rtc_interrupt, 0);
@@ -41,10 +42,12 @@ int main() {
asm volatile("cli");
// cputs("Initialize Serial\n");
cputs("Initialize Serial\n");
serial_init();
serial_puts("Hello from serial!\n");
fat32_init();
terminal_open(NULL);
terminal_write(0, "Terminal Write\n", 15);