Find kernel in second stage bootloader

sw/bios/Makefile

@@ -8,6 +8,8 @@ BIN=$(NAME).bin
 HEX=$(NAME).hex
 
 FPGA_IMG=../../hw/efinix_fpga/init_hex.mem
+EFX_RUN=/home/byron/Software/efinity/2023.1/scripts/efx_run.py
+EFX_PRJ=/home/byron/Projects/super6502/hw/efinix_fpga/super6502.xml
 
 LISTS=lists
 TESTS=tests
@@ -21,6 +23,7 @@ all: $(HEX)
 
 $(HEX): $(BIN)
 	objcopy --input-target=binary --output-target=verilog $(BIN) $(HEX)
+	cp boot2.bin ../fsdir
 	cmp $(HEX) $(FPGA_IMG); \
 	RETVAL=$$?; \
     if [ $$RETVAL -eq 0 ]; then \

sw/bios/boot2.s

@@ -1,26 +1,109 @@
-.importzp sp, ptr1, ptr2, ptr3, ptr4, tmp1, tmp2, tmp3, sreg
+.importzp sp, ptr1, ptr2, ptr3, ptr4, tmp1, tmp2, tmp3, sreg, data_start
 
 .autoimport on
 
+.export fatbuf
+
 .feature string_escapes
 
 .MACPACK generic
 
+fatbuf                  = $A000
+
 .segment "BOOTLOADER"
 
+sectors_per_cluster     = $800D
+reserved_sectors        = $800E
+fat_count               = $8010
+sectors_per_fat         = $8024
+
 _start:
         lda #<str
         ldx #>str
         jsr _cputs
 
-str: .byte "This is a very long message which would otherwise "
-     .byte "take up a lot of space in the bootsector, where space "
-     .byte "is at quite a premium. In fact, this string is as "
-     .byte "long as all the rest of the bootloader code, presuming "
-     .byte "I stretch it out long enough. It is quite remarkable "
-     .byte "Just how much you can do with so few bytes. Only a couple "
-     .byte "hundred are required to start up a modern computer. "
-     .byte "This is, of course, not a modern computer, but I want it "
-     .byte "to act like it in a way. This means using a modern "
-     .byte "(well, in the sense that its from 1996 and not 1983)"
-     .byte "anyway, I've exceeded 512 bytes now so good luck.", $00
+        ; Read root directory entry into fatbuf
+        lda data_start
+        ldx data_start + 1
+        jsr pushax
+        stz sreg
+        stz sreg+1
+        jsr pusheax
+        lda #<fatbuf
+        ldx #>fatbuf
+        jsr pushax
+        lda #<ptr1
+        ldx #>ptr1
+        jsr _SD_readSingleBlock
+
+        lda #<fatbuf
+        ldx #>fatbuf
+        jsr _SD_printBuf
+
+        lda #$20       ; Start at first directory entry (first is a disk label)
+        sta ptr3
+        lda #>fatbuf
+        sta ptr3 + 1
+        ldy #$0b        ; look for attributes
+@1:     lda (ptr3),y
+
+        cmp #$0f        ; if attribute is 0xf, this is a lfn
+        bne @2          ; if not an lfn, then try to read filename
+@next:  clc             ; otherwise, go to the next entry (+0x20)
+        lda ptr3
+        adc #$20
+        sta ptr3
+        lda #<word_str
+        ldx #>word_str
+        jsr pushax
+        lda ptr3
+        ldx ptr3 + 1
+        pha
+        phx
+        jsr pushax
+        phy
+        ldy #$4
+        jsr _cprintf
+        ply
+        plx
+        stx ptr3 + 1
+        pla
+        sta ptr3
+        bra @1
+
+@2:     ldy #11         ; ignore the attributes. Write null to make a string
+        lda #$00
+        sta (ptr3),y
+        lda ptr3        ; store address of the filename string on the stack
+        pha
+        ldx ptr3 + 1
+        phx
+        ; jsr _cputs              ; print out short filenames as we read them
+        lda #<kernel_str        ; load the string "KERNEL  O65"
+        ldx #>kernel_str        
+        jsr pushax
+        plx                     ; then push the string we read earlier
+        pla
+        jsr _strcmp
+        bne @next               ; if they are not equal then try next entry
+        lda #<_good             ; print match if we found it
+        ldx #>_good
+        jsr _cputs              ; otherwise continue on
+
+@3:     jmp @3
+
+; parse root directory for kernel.o65
+        ; load first data cluster (we know this is root.)
+        ; If kernel is not in this then we can go read the FAT
+        ; later. Saves time if kernel is near beginning
+
+        ; bootsector should still be loaded at $8000
+        ; data start should still be valid
+
+
+
+
+str: .asciiz "boot2\r\n"
+kernel_str: .asciiz "KERNEL  O65"
+_good: .asciiz "Found KERNEL"
+word_str: .asciiz "Word Value: %x\r\n"

sw/bios/bootloader.s

@@ -1,4 +1,5 @@
 .importzp sp, ptr1, ptr2, ptr3, ptr4, tmp1, tmp2, tmp3, sreg
+.exportzp data_start
 
 .autoimport on