Add some basic fat32 code

sw/kernel/devices/io.inc65

@@ -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

sw/kernel/devices/multiplier.h

@@ -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

sw/kernel/devices/multiplier.s

@@ -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

sw/kernel/filesystems/fat32.h

@@ -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

sw/kernel/filesystems/fat32.s

@@ -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

sw/kernel/filesystems/fs.h

@@ -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

sw/kernel/kernel.c

@@ -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);

sw/test_code/fs_test/Makefile

@@ -0,0 +1,48 @@
+CC=../../cc65/bin/cl65
+LD=../../cc65/bin/cl65
+SIM=../../cc65/bin/sim65 
+CFLAGS=-T -t sim65c02 -I.
+LDFLAGS=-m $(NAME).map
+
+NAME=fs_test
+
+BIN=$(NAME).bin
+
+FS=$(REPO_TOP)/sw/script/fs.fat
+
+LISTS=lists
+
+EXT_SRCS=$(REPO_TOP)/sw/kernel/filesystems/fat32.s
+
+SRCS=$(wildcard *.s) $(wildcard *.c)
+SRCS+=$(wildcard **/*.s) $(wildcard **/*.c)
+OBJS+=$(patsubst %.s,%.o,$(filter %s,$(SRCS)))
+OBJS+=$(patsubst %.c,%.o,$(filter %c,$(SRCS)))
+
+run: all
+	$(SIM) $(BIN)
+
+all: fs.fat fat32.s $(BIN)
+
+$(BIN): $(OBJS)
+	$(CC) $(CFLAGS) $(LDFLAGS) $(OBJS) -o $@
+
+%.o: %.c $(LISTS)
+	$(CC) $(CFLAGS) -l $(LISTS)/$<.list -c $< -o $@
+
+%.o: %.s $(LISTS)
+	$(CC) $(CFLAGS) -l $(LISTS)/$<.list -c $< -o $@
+
+fat32.s: $(EXT_SRCS)
+	cp $^ .
+
+fs.fat: $(FS)
+	cp $^ .
+
+$(LISTS):
+	mkdir -p $(addprefix $(LISTS)/,$(sort $(dir $(SRCS))))
+
+.PHONY: clean
+clean:
+	rm -rf $(OBJS) $(BIN) $(HEX) $(LISTS) $(NAME).map fat32.s
+

sw/test_code/fs_test/asm_harness.s

@@ -0,0 +1,5 @@
+.import _printf
+.export _cprintf
+
+_cprintf:
+    jmp _printf

sw/test_code/fs_test/harness.c

@@ -0,0 +1,21 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#define FILE_PATH "fs.fat"
+
+uint32_t lmulii(uint16_t a, uint16_t b) {
+    printf("lmulii: %x * %x = %x\n", a, b, a*b);
+    return a * b;
+}
+
+uint16_t imulii(uint16_t a, uint16_t b) {
+    printf("imulii: %x * %x = %x\n", a, b, a*b);
+    return a * b;
+}
+
+uint8_t SD_readSingleBlock(uint32_t addr, uint8_t *buf, uint8_t *error) {
+    FILE* f = fopen(FILE_PATH, "rb");
+    // fseek(f, addr * 512, SEEK_SET);
+    fread(buf, 512, 1, f);
+}

sw/test_code/fs_test/main.c

@@ -0,0 +1,9 @@
+#include <stdio.h>
+
+void fat32_init(void);
+
+int main(void) {
+    printf("Hello, world!\n");
+    fat32_init();
+    return 0;
+}