From c5f1b64cba5cdd59203d4a270a8716a43d92f607 Mon Sep 17 00:00:00 2001
From: Byron Lathi <bslathi19@gmail.com>
Date: Sat, 16 Apr 2022 21:43:26 -0500
Subject: [PATCH 1/8] Move filesystem code into its own directory

Step one into cleaning up the codebase a little bit.
---
 sw/Makefile               | 2 +-
 sw/exec.c                 | 4 ++--
 sw/{ => filesystem}/fat.c | 2 +-
 sw/{ => filesystem}/fat.h | 0
 sw/{ => filesystem}/o65.c | 0
 sw/{ => filesystem}/o65.h | 0
 sw/main.c                 | 3 +--
 7 files changed, 5 insertions(+), 6 deletions(-)
 rename sw/{ => filesystem}/fat.c (98%)
 rename sw/{ => filesystem}/fat.h (100%)
 rename sw/{ => filesystem}/o65.c (100%)
 rename sw/{ => filesystem}/o65.h (100%)

diff --git a/sw/Makefile b/sw/Makefile
index 3c85514..86e6789 100644
--- a/sw/Makefile
+++ b/sw/Makefile
@@ -15,7 +15,7 @@ LISTS=lists
 TESTS=tests
 
 SRCS=$(wildcard *.s) $(wildcard *.c)
-SRCS+=$(wildcard usb/*.c)
+SRCS+=$(wildcard filesystem/*.s) $(wildcard filesystem/*.c)
 OBJS+=$(patsubst %.s,%.o,$(filter %s,$(SRCS)))
 OBJS+=$(patsubst %.c,%.o,$(filter %c,$(SRCS)))
 
diff --git a/sw/exec.c b/sw/exec.c
index 8e3a622..0824eb6 100644
--- a/sw/exec.c
+++ b/sw/exec.c
@@ -2,8 +2,8 @@
 #include <conio.h>
 #include <string.h>
 
-#include "fat.h"
-#include "o65.h"
+#include "filesystem/fat.h"
+#include "filesystem/o65.h"
 
 void exec(char* filename) {
 	o65_header_t* header;
diff --git a/sw/fat.c b/sw/filesystem/fat.c
similarity index 98%
rename from sw/fat.c
rename to sw/filesystem/fat.c
index 5fb947f..7583210 100644
--- a/sw/fat.c
+++ b/sw/filesystem/fat.c
@@ -1,7 +1,7 @@
 #include <conio.h>
 #include <string.h>
 
-#include "fat.h"
+#include "filesystem/fat.h"
 #include "sd_card.h"
 
 uint8_t fat_buf[512];
diff --git a/sw/fat.h b/sw/filesystem/fat.h
similarity index 100%
rename from sw/fat.h
rename to sw/filesystem/fat.h
diff --git a/sw/o65.c b/sw/filesystem/o65.c
similarity index 100%
rename from sw/o65.c
rename to sw/filesystem/o65.c
diff --git a/sw/o65.h b/sw/filesystem/o65.h
similarity index 100%
rename from sw/o65.h
rename to sw/filesystem/o65.h
diff --git a/sw/main.c b/sw/main.c
index 23cdb63..f57a9cc 100644
--- a/sw/main.c
+++ b/sw/main.c
@@ -6,8 +6,7 @@
 #include "uart.h"
 #include "mapper.h"
 #include "sd_card.h"
-#include "fat.h"
-#include "o65.h"
+#include "filesystem/fat.h"
 #include "exec.h"
 
 uint8_t buf[512];

From 238a4b6f98c1d20194e49bafe7810806032b508a Mon Sep 17 00:00:00 2001
From: Byron Lathi <bslathi19@gmail.com>
Date: Sat, 16 Apr 2022 21:47:54 -0500
Subject: [PATCH 2/8] Move devices into devices folder

---
 sw/Makefile                    | 1 +
 sw/{ => devices}/board_io.h    | 0
 sw/{ => devices}/board_io.s    | 0
 sw/{ => devices}/conio.s       | 0
 sw/{ => devices}/interrupt.h   | 0
 sw/{ => devices}/interrupt.s   | 0
 sw/{ => devices}/io.inc65      | 0
 sw/{ => devices}/mapper.h      | 0
 sw/{ => devices}/mapper.s      | 0
 sw/{ => devices}/sd_card.c     | 2 +-
 sw/{ => devices}/sd_card.h     | 0
 sw/{ => devices}/sd_card_asm.s | 0
 sw/{ => devices}/uart.h        | 0
 sw/{ => devices}/uart.s        | 0
 sw/filesystem/fat.c            | 4 ++--
 sw/irq.c                       | 4 ++--
 sw/main.c                      | 8 ++++----
 17 files changed, 10 insertions(+), 9 deletions(-)
 rename sw/{ => devices}/board_io.h (100%)
 rename sw/{ => devices}/board_io.s (100%)
 rename sw/{ => devices}/conio.s (100%)
 rename sw/{ => devices}/interrupt.h (100%)
 rename sw/{ => devices}/interrupt.s (100%)
 rename sw/{ => devices}/io.inc65 (100%)
 rename sw/{ => devices}/mapper.h (100%)
 rename sw/{ => devices}/mapper.s (100%)
 rename sw/{ => devices}/sd_card.c (97%)
 rename sw/{ => devices}/sd_card.h (100%)
 rename sw/{ => devices}/sd_card_asm.s (100%)
 rename sw/{ => devices}/uart.h (100%)
 rename sw/{ => devices}/uart.s (100%)

diff --git a/sw/Makefile b/sw/Makefile
index 86e6789..1e984c9 100644
--- a/sw/Makefile
+++ b/sw/Makefile
@@ -16,6 +16,7 @@ TESTS=tests
 
 SRCS=$(wildcard *.s) $(wildcard *.c)
 SRCS+=$(wildcard filesystem/*.s) $(wildcard filesystem/*.c)
+SRCS+=$(wildcard devices/*.s) $(wildcard devices/*.c)
 OBJS+=$(patsubst %.s,%.o,$(filter %s,$(SRCS)))
 OBJS+=$(patsubst %.c,%.o,$(filter %c,$(SRCS)))
 
diff --git a/sw/board_io.h b/sw/devices/board_io.h
similarity index 100%
rename from sw/board_io.h
rename to sw/devices/board_io.h
diff --git a/sw/board_io.s b/sw/devices/board_io.s
similarity index 100%
rename from sw/board_io.s
rename to sw/devices/board_io.s
diff --git a/sw/conio.s b/sw/devices/conio.s
similarity index 100%
rename from sw/conio.s
rename to sw/devices/conio.s
diff --git a/sw/interrupt.h b/sw/devices/interrupt.h
similarity index 100%
rename from sw/interrupt.h
rename to sw/devices/interrupt.h
diff --git a/sw/interrupt.s b/sw/devices/interrupt.s
similarity index 100%
rename from sw/interrupt.s
rename to sw/devices/interrupt.s
diff --git a/sw/io.inc65 b/sw/devices/io.inc65
similarity index 100%
rename from sw/io.inc65
rename to sw/devices/io.inc65
diff --git a/sw/mapper.h b/sw/devices/mapper.h
similarity index 100%
rename from sw/mapper.h
rename to sw/devices/mapper.h
diff --git a/sw/mapper.s b/sw/devices/mapper.s
similarity index 100%
rename from sw/mapper.s
rename to sw/devices/mapper.s
diff --git a/sw/sd_card.c b/sw/devices/sd_card.c
similarity index 97%
rename from sw/sd_card.c
rename to sw/devices/sd_card.c
index 24646df..33bf986 100644
--- a/sw/sd_card.c
+++ b/sw/devices/sd_card.c
@@ -1,7 +1,7 @@
 #include <stdint.h>
 #include <conio.h>
 
-#include "sd_card.h"
+#include "devices/sd_card.h"
 
 void sd_init() {
 	uint32_t resp;
diff --git a/sw/sd_card.h b/sw/devices/sd_card.h
similarity index 100%
rename from sw/sd_card.h
rename to sw/devices/sd_card.h
diff --git a/sw/sd_card_asm.s b/sw/devices/sd_card_asm.s
similarity index 100%
rename from sw/sd_card_asm.s
rename to sw/devices/sd_card_asm.s
diff --git a/sw/uart.h b/sw/devices/uart.h
similarity index 100%
rename from sw/uart.h
rename to sw/devices/uart.h
diff --git a/sw/uart.s b/sw/devices/uart.s
similarity index 100%
rename from sw/uart.s
rename to sw/devices/uart.s
diff --git a/sw/filesystem/fat.c b/sw/filesystem/fat.c
index 7583210..e07359a 100644
--- a/sw/filesystem/fat.c
+++ b/sw/filesystem/fat.c
@@ -1,8 +1,8 @@
 #include <conio.h>
 #include <string.h>
 
-#include "filesystem/fat.h"
-#include "sd_card.h"
+#include "fat.h"
+#include "devices/sd_card.h"
 
 uint8_t fat_buf[512];
 
diff --git a/sw/irq.c b/sw/irq.c
index 313ea7d..4d2c0d8 100644
--- a/sw/irq.c
+++ b/sw/irq.c
@@ -2,8 +2,8 @@
 #include <stdint.h>
 #include <conio.h>
 
-#include "interrupt.h"
-#include "uart.h"
+#include "devices/interrupt.h"
+#include "devices/uart.h"
 
 char lastchar;
 
diff --git a/sw/main.c b/sw/main.c
index f57a9cc..c753882 100644
--- a/sw/main.c
+++ b/sw/main.c
@@ -2,10 +2,10 @@
 #include <conio.h>
 #include <string.h>
 
-#include "board_io.h"
-#include "uart.h"
-#include "mapper.h"
-#include "sd_card.h"
+#include "devices/board_io.h"
+#include "devices/uart.h"
+#include "devices/mapper.h"
+#include "devices/sd_card.h"
 #include "filesystem/fat.h"
 #include "exec.h"
 

From c6098f2d1ff3d60e9976e1e96dc1885d5e072337 Mon Sep 17 00:00:00 2001
From: Byron Lathi <bslathi19@gmail.com>
Date: Sat, 16 Apr 2022 21:58:37 -0500
Subject: [PATCH 3/8] Separate kernel code from test code

Eventually I want the kernel to be loaded from the SD card as well, but
it still needs to separate from user programs.

At some point there should be a folder just for the BIOS, which should
read from the boot block of the SD card and start executing, and thats
it.
---
 sw/{ => kernel}/Makefile              | 4 ++--
 sw/{ => kernel}/boot.s                | 0
 sw/{ => kernel}/devices/board_io.h    | 0
 sw/{ => kernel}/devices/board_io.s    | 0
 sw/{ => kernel}/devices/conio.s       | 0
 sw/{ => kernel}/devices/interrupt.h   | 0
 sw/{ => kernel}/devices/interrupt.s   | 0
 sw/{ => kernel}/devices/io.inc65      | 0
 sw/{ => kernel}/devices/mapper.h      | 0
 sw/{ => kernel}/devices/mapper.s      | 0
 sw/{ => kernel}/devices/sd_card.c     | 0
 sw/{ => kernel}/devices/sd_card.h     | 0
 sw/{ => kernel}/devices/sd_card_asm.s | 0
 sw/{ => kernel}/devices/uart.h        | 0
 sw/{ => kernel}/devices/uart.s        | 0
 sw/{ => kernel}/exec.c                | 0
 sw/{ => kernel}/exec.h                | 0
 sw/{ => kernel}/filesystem/fat.c      | 0
 sw/{ => kernel}/filesystem/fat.h      | 0
 sw/{ => kernel}/filesystem/o65.c      | 0
 sw/{ => kernel}/filesystem/o65.h      | 0
 sw/{ => kernel}/irq.c                 | 0
 sw/{ => kernel}/link.ld               | 0
 sw/{ => kernel}/main.c                | 0
 sw/{ => kernel}/tests/test_main.c     | 6 +++---
 sw/{ => kernel}/vectors.s             | 0
 26 files changed, 5 insertions(+), 5 deletions(-)
 rename sw/{ => kernel}/Makefile (89%)
 rename sw/{ => kernel}/boot.s (100%)
 rename sw/{ => kernel}/devices/board_io.h (100%)
 rename sw/{ => kernel}/devices/board_io.s (100%)
 rename sw/{ => kernel}/devices/conio.s (100%)
 rename sw/{ => kernel}/devices/interrupt.h (100%)
 rename sw/{ => kernel}/devices/interrupt.s (100%)
 rename sw/{ => kernel}/devices/io.inc65 (100%)
 rename sw/{ => kernel}/devices/mapper.h (100%)
 rename sw/{ => kernel}/devices/mapper.s (100%)
 rename sw/{ => kernel}/devices/sd_card.c (100%)
 rename sw/{ => kernel}/devices/sd_card.h (100%)
 rename sw/{ => kernel}/devices/sd_card_asm.s (100%)
 rename sw/{ => kernel}/devices/uart.h (100%)
 rename sw/{ => kernel}/devices/uart.s (100%)
 rename sw/{ => kernel}/exec.c (100%)
 rename sw/{ => kernel}/exec.h (100%)
 rename sw/{ => kernel}/filesystem/fat.c (100%)
 rename sw/{ => kernel}/filesystem/fat.h (100%)
 rename sw/{ => kernel}/filesystem/o65.c (100%)
 rename sw/{ => kernel}/filesystem/o65.h (100%)
 rename sw/{ => kernel}/irq.c (100%)
 rename sw/{ => kernel}/link.ld (100%)
 rename sw/{ => kernel}/main.c (100%)
 rename sw/{ => kernel}/tests/test_main.c (95%)
 rename sw/{ => kernel}/vectors.s (100%)

diff --git a/sw/Makefile b/sw/kernel/Makefile
similarity index 89%
rename from sw/Makefile
rename to sw/kernel/Makefile
index 1e984c9..dd043a4 100644
--- a/sw/Makefile
+++ b/sw/kernel/Makefile
@@ -15,8 +15,7 @@ LISTS=lists
 TESTS=tests
 
 SRCS=$(wildcard *.s) $(wildcard *.c)
-SRCS+=$(wildcard filesystem/*.s) $(wildcard filesystem/*.c)
-SRCS+=$(wildcard devices/*.s) $(wildcard devices/*.c)
+SRCS+=$(filter-out $(wildcard tests/*), $(wildcard **/*.s)) $(filter-out $(wildcard tests/*), $(wildcard **/*.c))
 OBJS+=$(patsubst %.s,%.o,$(filter %s,$(SRCS)))
 OBJS+=$(patsubst %.c,%.o,$(filter %c,$(SRCS)))
 
@@ -47,6 +46,7 @@ $(BIN): $(OBJS)
 	$(CC) $(CFLAGS) -l $(LISTS)/$<.list -c $< -o $@
 
 $(LISTS):
+	$(info $$SRCS is [${SRCS}])
 	mkdir -p $(addprefix $(LISTS)/,$(sort $(dir $(SRCS))))
 	mkdir $(LISTS)/$(sort $(dir $(TEST_SRCS)))
 
diff --git a/sw/boot.s b/sw/kernel/boot.s
similarity index 100%
rename from sw/boot.s
rename to sw/kernel/boot.s
diff --git a/sw/devices/board_io.h b/sw/kernel/devices/board_io.h
similarity index 100%
rename from sw/devices/board_io.h
rename to sw/kernel/devices/board_io.h
diff --git a/sw/devices/board_io.s b/sw/kernel/devices/board_io.s
similarity index 100%
rename from sw/devices/board_io.s
rename to sw/kernel/devices/board_io.s
diff --git a/sw/devices/conio.s b/sw/kernel/devices/conio.s
similarity index 100%
rename from sw/devices/conio.s
rename to sw/kernel/devices/conio.s
diff --git a/sw/devices/interrupt.h b/sw/kernel/devices/interrupt.h
similarity index 100%
rename from sw/devices/interrupt.h
rename to sw/kernel/devices/interrupt.h
diff --git a/sw/devices/interrupt.s b/sw/kernel/devices/interrupt.s
similarity index 100%
rename from sw/devices/interrupt.s
rename to sw/kernel/devices/interrupt.s
diff --git a/sw/devices/io.inc65 b/sw/kernel/devices/io.inc65
similarity index 100%
rename from sw/devices/io.inc65
rename to sw/kernel/devices/io.inc65
diff --git a/sw/devices/mapper.h b/sw/kernel/devices/mapper.h
similarity index 100%
rename from sw/devices/mapper.h
rename to sw/kernel/devices/mapper.h
diff --git a/sw/devices/mapper.s b/sw/kernel/devices/mapper.s
similarity index 100%
rename from sw/devices/mapper.s
rename to sw/kernel/devices/mapper.s
diff --git a/sw/devices/sd_card.c b/sw/kernel/devices/sd_card.c
similarity index 100%
rename from sw/devices/sd_card.c
rename to sw/kernel/devices/sd_card.c
diff --git a/sw/devices/sd_card.h b/sw/kernel/devices/sd_card.h
similarity index 100%
rename from sw/devices/sd_card.h
rename to sw/kernel/devices/sd_card.h
diff --git a/sw/devices/sd_card_asm.s b/sw/kernel/devices/sd_card_asm.s
similarity index 100%
rename from sw/devices/sd_card_asm.s
rename to sw/kernel/devices/sd_card_asm.s
diff --git a/sw/devices/uart.h b/sw/kernel/devices/uart.h
similarity index 100%
rename from sw/devices/uart.h
rename to sw/kernel/devices/uart.h
diff --git a/sw/devices/uart.s b/sw/kernel/devices/uart.s
similarity index 100%
rename from sw/devices/uart.s
rename to sw/kernel/devices/uart.s
diff --git a/sw/exec.c b/sw/kernel/exec.c
similarity index 100%
rename from sw/exec.c
rename to sw/kernel/exec.c
diff --git a/sw/exec.h b/sw/kernel/exec.h
similarity index 100%
rename from sw/exec.h
rename to sw/kernel/exec.h
diff --git a/sw/filesystem/fat.c b/sw/kernel/filesystem/fat.c
similarity index 100%
rename from sw/filesystem/fat.c
rename to sw/kernel/filesystem/fat.c
diff --git a/sw/filesystem/fat.h b/sw/kernel/filesystem/fat.h
similarity index 100%
rename from sw/filesystem/fat.h
rename to sw/kernel/filesystem/fat.h
diff --git a/sw/filesystem/o65.c b/sw/kernel/filesystem/o65.c
similarity index 100%
rename from sw/filesystem/o65.c
rename to sw/kernel/filesystem/o65.c
diff --git a/sw/filesystem/o65.h b/sw/kernel/filesystem/o65.h
similarity index 100%
rename from sw/filesystem/o65.h
rename to sw/kernel/filesystem/o65.h
diff --git a/sw/irq.c b/sw/kernel/irq.c
similarity index 100%
rename from sw/irq.c
rename to sw/kernel/irq.c
diff --git a/sw/link.ld b/sw/kernel/link.ld
similarity index 100%
rename from sw/link.ld
rename to sw/kernel/link.ld
diff --git a/sw/main.c b/sw/kernel/main.c
similarity index 100%
rename from sw/main.c
rename to sw/kernel/main.c
diff --git a/sw/tests/test_main.c b/sw/kernel/tests/test_main.c
similarity index 95%
rename from sw/tests/test_main.c
rename to sw/kernel/tests/test_main.c
index 0ce03a9..99e3dd8 100644
--- a/sw/tests/test_main.c
+++ b/sw/kernel/tests/test_main.c
@@ -1,8 +1,8 @@
 #include <stdio.h>
 
-#include "board_io.h"
-#include "uart.h"
-#include "interrupt.h"
+#include "devices/board_io.h"
+#include "devices/uart.h"
+#include "devices/interrupt.h"
 
 int main(void)
 {
diff --git a/sw/vectors.s b/sw/kernel/vectors.s
similarity index 100%
rename from sw/vectors.s
rename to sw/kernel/vectors.s

From 8495f1f002a5f19a65e50c32c8b8699bc9f8226c Mon Sep 17 00:00:00 2001
From: Byron Lathi <bslathi19@gmail.com>
Date: Sat, 16 Apr 2022 22:02:18 -0500
Subject: [PATCH 4/8] Update ci

---
 .gitlab-ci.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 04a587b..4213a4b 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -2,11 +2,11 @@ default:
   tags:
     - docker
 
-build-sw:
+build-kernel:
   stage: build
   image: a2geek/cc65-pipeline
   script:
-    - cd sw/
+    - cd sw/kernel
     - make
 
 

From 6844c48a3bc0220d823f2b8fad1476e338a34305 Mon Sep 17 00:00:00 2001
From: Byron Lathi <bslathi19@gmail.com>
Date: Sat, 16 Apr 2022 22:07:19 -0500
Subject: [PATCH 5/8] Update ci

---
 .gitlab-ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 4213a4b..3a766bf 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -36,7 +36,7 @@ test-sw:
   stage: test
   image: a2geek/cc65-pipeline
   script:
-    - cd sw/
+    - cd sw/kernel
     - make test
 
 test_mm:

From edd13e9b71008ed36d7f1d4469bf896da0db6ce8 Mon Sep 17 00:00:00 2001
From: Byron Lathi <bslathi19@gmail.com>
Date: Sun, 17 Apr 2022 18:11:45 -0500
Subject: [PATCH 6/8] Remove debug information

---
 sw/kernel/Makefile | 1 -
 1 file changed, 1 deletion(-)

diff --git a/sw/kernel/Makefile b/sw/kernel/Makefile
index dd043a4..a84801d 100644
--- a/sw/kernel/Makefile
+++ b/sw/kernel/Makefile
@@ -46,7 +46,6 @@ $(BIN): $(OBJS)
 	$(CC) $(CFLAGS) -l $(LISTS)/$<.list -c $< -o $@
 
 $(LISTS):
-	$(info $$SRCS is [${SRCS}])
 	mkdir -p $(addprefix $(LISTS)/,$(sort $(dir $(SRCS))))
 	mkdir $(LISTS)/$(sort $(dir $(TEST_SRCS)))
 

From 52f631e5580acd5513c31ee1f9c0483b2cf82e07 Mon Sep 17 00:00:00 2001
From: Byron Lathi <bslathi19@gmail.com>
Date: Sun, 17 Apr 2022 18:12:13 -0500
Subject: [PATCH 7/8] Allow finding files in the root directory

This allows you to find the cluster number of a file in the root
directory by name. The main program is a simple demo where you can type
in a filename and it will tell you the cluster number.
---
 sw/kernel/filesystem/fat.c | 192 ++++++++++++++++++++++++++++++++-----
 sw/kernel/filesystem/fat.h |  15 ++-
 sw/kernel/main.c           |  14 ++-
 3 files changed, 193 insertions(+), 28 deletions(-)

diff --git a/sw/kernel/filesystem/fat.c b/sw/kernel/filesystem/fat.c
index e07359a..669b0a5 100644
--- a/sw/kernel/filesystem/fat.c
+++ b/sw/kernel/filesystem/fat.c
@@ -1,55 +1,65 @@
 #include <conio.h>
 #include <string.h>
+#include <stdlib.h>
 
 #include "fat.h"
 #include "devices/sd_card.h"
 
 uint8_t fat_buf[512];
 
+static uint32_t fat_end_of_chain;
+
 static full_bpb_t bpb;
 
 static uint32_t data_region_start;
 
-void fat_print_pbp_info(ebpb_t* epbp){
-	cprintf("Bytes per sector: %d\n", epbp->bpb3.bpb2.bytes_per_sector);
-	cprintf("Sectors per cluster: %d\n", epbp->bpb3.bpb2.sectors_per_cluster);
-	cprintf("Reserved Sectors: %d\n", epbp->bpb3.bpb2.reserved_sectors);
-	cprintf("Fat Count: %d\n", epbp->bpb3.bpb2.fat_count);
-	cprintf("Max Dir Entries: %d\n", epbp->bpb3.bpb2.max_dir_entries);
-	cprintf("Total Sector Count: %d\n", epbp->bpb3.bpb2.total_sector_count);
-	cprintf("Media Descriptor: 0x%x\n", epbp->bpb3.bpb2.media_descriptor);
-	cprintf("Sectors per Fat: %d\n", epbp->bpb3.bpb2.sectors_per_fat);
+void fat_print_pbp_info(full_bpb_t* bpb){
+	cprintf("Bytes per sector: %d\n", bpb->bytes_per_sector);
+	cprintf("Sectors per cluster: %d\n", bpb->sectors_per_cluster);
+	cprintf("Reserved Sectors: %d\n", bpb->reserved_sectors);
+	cprintf("Fat Count: %d\n", bpb->fat_count);
+	cprintf("Max Dir Entries: %d\n", bpb->max_dir_entries);
+	cprintf("Total Sector Count: %d\n", bpb->total_sector_count);
+	cprintf("Media Descriptor: 0x%x\n", bpb->media_descriptor);
+	cprintf("Sectors per Fat: %d\n", bpb->sectors_per_fat_16);
 	cprintf("\n");
 
-	cprintf("Sectors per track: %d\n", epbp->bpb3.sectors_per_track);
-	cprintf("Head Count: %d\n", epbp->bpb3.head_count);
-	cprintf("Hidden Sector Count: %ld\n", epbp->bpb3.hidden_sector_count);
-	cprintf("Logical Sector Count: %ld\n", epbp->bpb3.logical_sector_count);
-	cprintf("Sectors per Fat: %ld\n", epbp->bpb3.sectors_per_fat);
-	cprintf("Extended Flags: 0x%x\n", epbp->bpb3.extended_flags);
-	cprintf("Version: %d\n", epbp->bpb3.version);
-	cprintf("Root Cluster: 0x%lx\n", epbp->bpb3.root_cluster);
-	cprintf("System Information: 0x%x\n", epbp->bpb3.system_information);
-	cprintf("Backup Boot Sector: 0x%x\n", epbp->bpb3.backup_boot_sector);
+	cprintf("Sectors per track: %d\n", bpb->sectors_per_track);
+	cprintf("Head Count: %d\n", bpb->head_count);
+	cprintf("Hidden Sector Count: %ld\n", bpb->hidden_sector_count);
+	cprintf("Logical Sector Count: %ld\n", bpb->logical_sector_count);
+	cprintf("Sectors per Fat: %ld\n", bpb->sectors_per_fat_32);
+	cprintf("Extended Flags: 0x%x\n", bpb->extended_flags);
+	cprintf("Version: %d\n", bpb->version);
+	cprintf("Root Cluster: 0x%lx\n", bpb->root_cluster);
+	cprintf("System Information: 0x%x\n", bpb->system_information);
+	cprintf("Backup Boot Sector: 0x%x\n", bpb->backup_boot_sector);
 	cprintf("\n");
 
-	cprintf("Drive Number: %d\n", epbp->drive_num);
-	cprintf("Extended Signature: 0x%x\n", epbp->extended_signature);
-	cprintf("Volume ID: 0x%lx\n", epbp->volume_id);
-	cprintf("Partition Label: %.11s\n", &epbp->partition_label);
-	cprintf("Partition Label: %.8s\n", &epbp->filesystem_type);
+	cprintf("Drive Number: %d\n", bpb->drive_num);
+	cprintf("Extended Signature: 0x%x\n", bpb->extended_signature);
+	cprintf("Volume ID: 0x%lx\n", bpb->volume_id);
+	cprintf("Partition Label: %.11s\n", &bpb->partition_label);
+	cprintf("Partition Label: %.8s\n", &bpb->filesystem_type);
 	cprintf("\n");
 }
 
 void fat_init(){
     sd_readblock(0, fat_buf);
 
-    memcpy(&bpb, &fat_buf[11], sizeof(ebpb_t));
+    memcpy(&bpb, &fat_buf[11], sizeof(full_bpb_t));
 
 	sd_readblock(1, fat_buf);
 	sd_readblock(32, fat_buf);
 
+	fat_print_pbp_info(&bpb);
+
 	data_region_start = bpb.reserved_sectors + bpb.fat_count*bpb.sectors_per_fat_32;
+
+	sd_readblock(bpb.reserved_sectors, fat_buf);
+
+	fat_end_of_chain = ((uint32_t*)fat_buf)[1] & FAT_EOC_CLUSTERMASK;
+	cprintf("End of chain indicator: %lx\n", fat_end_of_chain);
 }
 
 void fat_read(char* filename, void* buf) {
@@ -71,3 +81,135 @@ void fat_read(char* filename, void* buf) {
 
 	sd_readblock(data_region_start + (cluster - 2) * 8, buf);
 }
+
+//the dentry is a double pointer because we need to increment it.
+void fat_parse_vfat_filenamename(vfat_dentry_t** vfat_dentry, char* name) {
+	uint8_t i;
+	uint8_t done;
+	char* shift_name;
+	uint8_t sequence_number = (*vfat_dentry)->sequence_number;
+
+	// so basically we want to add 13*(sequence number-1) to name
+
+	for (;;){
+		shift_name = name + 13*((sequence_number & FAT_LFN_ENTRY_MASK) - 1);
+
+		done = 0;
+		for(i = 0; i < 5; i++) {
+			shift_name[i] = (*vfat_dentry)->filename0[i];
+			if (!shift_name[i]) {
+				done = 1;
+				break;
+			}
+		}
+
+		if (!done) {
+			for(i = 0; i < 6; i++) {
+				shift_name[i+5] = (*vfat_dentry)->filename1[i];
+				if (!shift_name[i+5]) {
+					done = 1;
+					break;
+				}
+			}
+		}
+
+		if (!done) {
+			for(i = 0; i < 2; i++) {
+				shift_name[i+11] = (*vfat_dentry)->filename2[i];
+				if (!shift_name[i+11]) {
+					done = 1;
+					break;
+				}
+			}
+		}
+
+		if ((sequence_number & FAT_LFN_ENTRY_MASK) == 1) {
+			break;
+		} else {
+			(*vfat_dentry)++;
+			while((*vfat_dentry)->sequence_number == 0xe5)
+				(*vfat_dentry)++;
+			sequence_number = (*vfat_dentry)->sequence_number;
+		}
+	}
+
+}
+
+uint32_t fat_find_cluster_num(char* name, uint32_t cluster) {
+	vfat_dentry_t* vfat_dentry;
+	dos_dentry_t* dos_dentry;
+	char* vfat_name;
+
+	cprintf("Looking for file %s\n", name);
+
+	sd_readblock(data_region_start + (cluster - 2) * 8, fat_buf);
+	vfat_dentry = (vfat_dentry_t*)fat_buf;
+
+	vfat_name = (char*)malloc(FAT_MAX_FILE_NAME);
+
+	while(vfat_dentry->sequence_number == 0xe5)
+		vfat_dentry++;
+
+	vfat_name[0] = '\0';
+
+	while(vfat_dentry->sequence_number) {
+		fat_parse_vfat_filenamename(&vfat_dentry, vfat_name);
+		cprintf("Parsed filename: %s\n", vfat_name);
+
+		if (!strcmp(vfat_name, name)) {				//TODO this is probably unsafe, use strncmp
+			cprintf("Found file %s\n", vfat_name);
+			break;
+		} else {
+			vfat_dentry += 2;
+			while(vfat_dentry->sequence_number == 0xe5)
+				vfat_dentry++;
+		}
+	}
+
+	free(vfat_name);
+
+	if (!vfat_dentry->sequence_number) {
+		cprintf("File not found.\n");
+		return -1;
+	}
+
+	dos_dentry = (dos_dentry_t*) vfat_dentry + 1;	//dos entry follows last vfat entry
+
+	cluster = ((uint32_t)dos_dentry->first_cluster_h << 16) + dos_dentry->first_cluster_l;
+	cprintf("Cluster: %ld\n", cluster);
+
+	return cluster;
+}
+
+uint16_t fat_parse_path_to_cluster(char* filename) {
+	//basically start at the root folder and search through it
+	int i;
+	int len;
+
+	char* spaced_filename;
+
+	uint32_t cluster = 2;	//root chain is chain 2
+
+	if (filename[0] != '/') {
+		cprintf("Filename does not begin with '/'\n");
+		return 0;
+	}
+
+	filename++;
+	len = strlen(filename);
+	spaced_filename = (char*)malloc(len+1);	//need to account for null byte
+
+	for (i = 0; i <= len; i++) {
+		if (filename[i] == '/') {
+			spaced_filename[i] = '\0';
+		} else {
+			spaced_filename[i] = filename[i];
+		}
+	}
+
+	cprintf("Fragment: %s\n", spaced_filename);
+
+	fat_find_cluster_num(spaced_filename, cluster);
+
+	free(spaced_filename);
+}
diff --git a/sw/kernel/filesystem/fat.h b/sw/kernel/filesystem/fat.h
index bf374ab..9c26b5b 100644
--- a/sw/kernel/filesystem/fat.h
+++ b/sw/kernel/filesystem/fat.h
@@ -5,6 +5,15 @@
 
 extern uint8_t fat_buf[];
 
+#define FAT_MAX_FILE_NAME 255
+#define FAT_CLUSTERS_PER_SECTOR 128
+
+#define FAT_CLUSTERMASK 0x0fffffff
+#define FAT_EOC_CLUSTERMASK 0x0ffffff8
+
+#define FAT_LAST_LFN_MASK (1 << 6)
+#define FAT_LFN_ENTRY_MASK 0x1f
+
 typedef struct {
     uint16_t bytes_per_sector;
     uint8_t sectors_per_cluster;
@@ -87,7 +96,7 @@ typedef struct {
     uint8_t checksum;
     uint16_t filename1[6];
     uint16_t reserved;
-    uint16_t filename[2];
+    uint16_t filename2[2];
 } vfat_dentry_t;
 
 typedef struct {
@@ -104,8 +113,10 @@ typedef struct {
     uint32_t file_size;
 } dos_dentry_t;
 
-void fat_print_pbp_info(ebpb_t* epbp);
+void fat_print_pbp_info(full_bpb_t* bpb);
 void fat_init();
 void fat_read(char* filename, void* buf);
 
+uint16_t fat_parse_path_to_cluster(char* filename);
+
 #endif
diff --git a/sw/kernel/main.c b/sw/kernel/main.c
index c753882..21850fd 100644
--- a/sw/kernel/main.c
+++ b/sw/kernel/main.c
@@ -1,6 +1,7 @@
 #include <stdint.h>
 #include <conio.h>
 #include <string.h>
+#include <stdlib.h>
 
 #include "devices/board_io.h"
 #include "devices/uart.h"
@@ -14,6 +15,7 @@ uint8_t buf[512];
 int main() {
 	int i;
 	uint16_t rca;
+	char* filename;
 
 	clrscr();
 	cprintf("Hello, world!\n");
@@ -34,7 +36,17 @@ int main() {
 	sd_select_card(rca);
 
 	fat_init();
-	exec("/test.o65");
+
+	filename = (char*)malloc(FAT_MAX_FILE_NAME);
+
+	for(;;) {
+		cprintf("Filename: ");
+		cscanf("%s", filename);
+		cprintf("\n");
+		fat_parse_path_to_cluster(filename);
+	}
+
+	//exec("/test.o65");
 
 	cprintf("Done!\n");
 

From a9d9bc06196f7dc26d65e5c31776ddb59838cb1e Mon Sep 17 00:00:00 2001
From: Byron Lathi <bslathi19@gmail.com>
Date: Sun, 17 Apr 2022 20:17:22 -0500
Subject: [PATCH 8/8] Allow subdirectories

Can now break apart a filepath into the parent directories and search
for each one of them (not recursively!).
---
 sw/kernel/filesystem/fat.c | 47 +++++++++++++++++++++++++++++++-------
 1 file changed, 39 insertions(+), 8 deletions(-)

diff --git a/sw/kernel/filesystem/fat.c b/sw/kernel/filesystem/fat.c
index 669b0a5..e5187f3 100644
--- a/sw/kernel/filesystem/fat.c
+++ b/sw/kernel/filesystem/fat.c
@@ -45,6 +45,8 @@ void fat_print_pbp_info(full_bpb_t* bpb){
 }
 
 void fat_init(){
+	int i;
+
     sd_readblock(0, fat_buf);
 
     memcpy(&bpb, &fat_buf[11], sizeof(full_bpb_t));
@@ -58,6 +60,15 @@ void fat_init(){
 
 	sd_readblock(bpb.reserved_sectors, fat_buf);
 
+	//uncomment to view start of FAT
+
+	/*
+	for (i = 0; i < FAT_CLUSTERS_PER_SECTOR; i++) {
+		cprintf("%lx ", ((uint32_t*)fat_buf)[i]);
+	}
+	cprintf("\n\n");
+	*/
+
 	fat_end_of_chain = ((uint32_t*)fat_buf)[1] & FAT_EOC_CLUSTERMASK;
 	cprintf("End of chain indicator: %lx\n", fat_end_of_chain);
 }
@@ -83,13 +94,13 @@ void fat_read(char* filename, void* buf) {
 }
 
 //the dentry is a double pointer because we need to increment it.
-void fat_parse_vfat_filenamename(vfat_dentry_t** vfat_dentry, char* name) {
+void fat_parse_vfat_filenamename(vfat_dentry_t** vfat_dentry, char* name, uint32_t cluster) {
 	uint8_t i;
+	uint8_t overflows;
 	uint8_t done;
 	char* shift_name;
 	uint8_t sequence_number = (*vfat_dentry)->sequence_number;
-
-	// so basically we want to add 13*(sequence number-1) to name
+	overflows = 0;
 
 	for (;;){
 		shift_name = name + 13*((sequence_number & FAT_LFN_ENTRY_MASK) - 1);
@@ -126,9 +137,18 @@ void fat_parse_vfat_filenamename(vfat_dentry_t** vfat_dentry, char* name) {
 		if ((sequence_number & FAT_LFN_ENTRY_MASK) == 1) {
 			break;
 		} else {
-			(*vfat_dentry)++;
-			while((*vfat_dentry)->sequence_number == 0xe5)
+			do {
 				(*vfat_dentry)++;
+				if ((uint8_t*)*vfat_dentry >= fat_buf + sizeof(fat_buf)) {
+					overflows++;
+					if (overflows == bpb.sectors_per_cluster) {
+						cprintf("Too many overflows, go back to fat!\n");		//TODO this
+						return;
+					}
+					sd_readblock(data_region_start + (cluster - 2) * 8 + overflows, fat_buf);
+					*vfat_dentry = (vfat_dentry_t*)fat_buf;
+				}
+			} while((*vfat_dentry)->sequence_number == 0xe5);
 			sequence_number = (*vfat_dentry)->sequence_number;
 		}
 	}
@@ -153,7 +173,7 @@ uint32_t fat_find_cluster_num(char* name, uint32_t cluster) {
 	vfat_name[0] = '\0';
 
 	while(vfat_dentry->sequence_number) {
-		fat_parse_vfat_filenamename(&vfat_dentry, vfat_name);
+		fat_parse_vfat_filenamename(&vfat_dentry, vfat_name, cluster);
 		cprintf("Parsed filename: %s\n", vfat_name);
 
 		if (!strcmp(vfat_name, name)) {				//TODO this is probably unsafe, use strncmp
@@ -185,8 +205,10 @@ uint16_t fat_parse_path_to_cluster(char* filename) {
 	//basically start at the root folder and search through it
 	int i;
 	int len;
+	uint8_t dirs = 0;
 
 	char* spaced_filename;
+	char* fragment;
 
 	uint32_t cluster = 2;	//root chain is chain 2
 
@@ -202,14 +224,23 @@ uint16_t fat_parse_path_to_cluster(char* filename) {
 	for (i = 0; i <= len; i++) {
 		if (filename[i] == '/') {
 			spaced_filename[i] = '\0';
+			dirs++;
 		} else {
 			spaced_filename[i] = filename[i];
 		}
 	}
 
-	cprintf("Fragment: %s\n", spaced_filename);
+	fragment = spaced_filename;
 
-	fat_find_cluster_num(spaced_filename, cluster);
+	cprintf("Dirs: %d\n", dirs);
+
+	for (i = 0; i <= dirs; i++) {
+		cprintf("Fragment: %s\n", fragment);
+		cluster = fat_find_cluster_num(fragment, cluster);
+		fragment = spaced_filename + strlen(fragment) + 1;
+	}
 
 	free(spaced_filename);
+
+	return cluster;
 }