got multiboot info parsed!

makefile

@@ -5,13 +5,14 @@ cd: kernel fs
 	grub2-mkrescue out/fs -o out/cd.iso --product-name=portland --product-version=0.0.9
 
 kernel: obj out
-	nasm src/kernel/stub.asm -o obj/kstub.o -f elf32
+	nasm src/kernel/serial.asm -o obj/kserial.o -f elf32
-	gcc -c src/kernel/files.c -o obj/kfiles.o -ffreestanding -nostdlib -m32
+	nasm src/kernel/stub.asm   -o obj/kstub.o   -f elf32
-	gcc -c src/kernel/main.c  -o obj/kmain.o  -ffreestanding -nostdlib -m32
+	gcc -c src/kernel/files.c  -o obj/kfiles.o  -ffreestanding -nostdlib -m32
-	gcc -c src/kernel/mem.c   -o obj/kmem.o   -ffreestanding -nostdlib -m32
+	gcc -c src/kernel/main.c   -o obj/kmain.o   -ffreestanding -nostdlib -m32
-	gcc -c src/kernel/proc.c  -o obj/kproc.o  -ffreestanding -nostdlib -m32
+	gcc -c src/kernel/mem.c    -o obj/kmem.o    -ffreestanding -nostdlib -m32
-	gcc -c src/kernel/vga.c   -o obj/kvga.o   -ffreestanding -nostdlib -m32
+	gcc -c src/kernel/proc.c   -o obj/kproc.o   -ffreestanding -nostdlib -m32
-	ld obj/kstub.o obj/kfiles.o obj/kmain.o obj/kmem.o obj/kproc.o obj/kvga.o \
+	gcc -c src/kernel/vga.c    -o obj/kvga.o    -ffreestanding -nostdlib -m32
+	ld obj/kstub.o obj/kfiles.o obj/kmain.o obj/kmem.o obj/kproc.o obj/kserial.o obj/kvga.o \
 		-o out/kernel.elf -T src/kernel/link.ld -s --orphan-handling=discard -melf_i386
 
 

src/kernel/main.c

@@ -23,8 +23,6 @@ OF THIS SOFTWARE.
 #include "proc.h"
 #include <stdbool.h>
 
-extern uint32_t info_pointer;
-
 enum tag_type {
   BOOT_COMMAND     =  1,
   LOADER_NAME      =  2,
@@ -52,7 +50,6 @@ enum tag_type {
 struct tag_start {
   uint32_t type;
   uint32_t size;
-  uint8_t rest;
 } __attribute__ ((__packed__));
 
 struct boot_device_tag {
@@ -79,52 +76,68 @@ bool have_boot_device = false;
 bool have_mmap = false;
 
 enum error_codes {
-  NO_BOOT_DEVICE = 000000000000,
+  NO_BOOT_DEVICE = 0x00000000,
-  NO_MMAP        = 000000000001,
+  NO_MMAP        = 0x00000001,
-  INSUFF_MEMORY  = 000000000002
+  INSUFF_MEMORY  = 0x00000002
 };
 
+struct tag_start *tag_pointer;
+
 uint32_t main(void) {
-  for (uint32_t *i = (uint32_t *)VGA_BUFFER; i < (uint32_t *)0x000b8fa0; ++i)
+  clear();
-    *i = 0x70207020;
 
-  put_sz("Starting...\n");
+  /*
-
+  uint32_t *debug_ptr = (uint32_t *)tag_pointer - 2;
-  uint32_t info_size = *(uint32_t *)info_pointer;
+  uint32_t debug_size = *debug_ptr / 4;
-  struct tag_start *tag_pointer = (struct tag_start *)(info_pointer + 2);
+  for (uint32_t i = 0; i < debug_size; ++i) {
+    put_32_hex(debug_ptr[i]);
+    put_char(' ');
+  }
+  */
 
+  put_sz("Multiboot info:\n");
   while (tag_pointer->type) {
+    put_sz("  Tag type 0x");
+    put_32_hex(tag_pointer->type);
+    put_sz(" with size 0x");
+    put_32_hex(tag_pointer->size);
     switch (tag_pointer->type) {
 
     case BOOT_DEVICE:
-      boot_device = *(struct boot_device_tag *)&tag_pointer->rest;
+      boot_device = *(struct boot_device_tag *)(tag_pointer + 1);
       have_boot_device = true;
-      put_sz("Boot device: 0x");
+      put_sz(": boot device\n    BIOS code: ");
       put_32_hex(boot_device.bios_device);
       if (boot_device.partition != 0xffffffff) {
-        put_sz(", 0x");
+        put_sz("\n      Partition number: ");
         put_32_hex(boot_device.partition);
         if (boot_device.subpartition != 0xffffffff) {
-          put_sz(", 0x");
+          put_sz("\n      Subpartition number: ");
           put_32_hex(boot_device.subpartition);
+          put_char('\n');
         }
+        else
+          put_sz("\n    No subpartition\n");
       }
-      put_char('\n');
+      else
+        put_sz("\n    No partition\n");
       break;
 
     case MEMORY_MAP:
     {
-      struct mmap_tag_entry *tag = (struct mmap_tag_entry *)((uint32_t)&tag_pointer->rest + 8);
+      uint32_t size = *(uint32_t *)(tag_pointer + 1);
-      uint32_t size = *(uint32_t *)&tag_pointer->rest;
+      struct mmap_tag_entry *tag = (struct mmap_tag_entry *)(tag_pointer + 2);
+      struct mmap_tag_entry *end = (struct mmap_tag_entry *)((uint32_t)tag_pointer + tag_pointer->size);
       struct mmap_entry *entry = (struct mmap_entry *)tag;
       struct mmap_entry **last_next = &mmap_start;
       uint32_t usable = 0;
-      while (tag) {
+      put_sz(": memory map\n    Regions:\n");
+      while (tag != end) {
         if (!(tag->base & 0xffffffff00000000)) {
           entry->base = (uint32_t)tag->base;
           entry->length = (tag->base + tag->length - 1) & 0xffffffff00000000 ?
             1 + ~(uint32_t)tag->base : (uint32_t)tag->length;
-          put_sz("Memory: 0x");
+          put_sz("      0x");
           put_32_hex(entry->base);
           put_sz(" - 0x");
           put_32_hex(entry->base + entry->length - 1);
@@ -147,7 +160,9 @@ uint32_t main(void) {
             entry->whose = HARDWARE;
             break;
           default:
-            put_sz(": unrecognized type, assuming hardware use\n");
+            put_sz(": hardware use (0x");
+            put_32_hex(tag->type);
+            put_sz(")\n");
             entry->whose = HARDWARE;
             break;
           }
@@ -158,13 +173,13 @@ uint32_t main(void) {
         tag = (struct mmap_tag_entry *)((uint32_t)tag + size);
       }
 
-      put_sz("Total usable memory: 0x");
+      put_sz("    Total usable memory: ");
       put_32_hex(usable);
       put_char('\n');
 
-      bool clean;
+      bool dirty;
       do {
-        clean = true;
+        dirty = false;
         for (struct mmap_entry *current = mmap_start; current; current = current->next)
           for (struct mmap_entry *against = mmap_start; against; against = against->next)
             if ((current->base + current->length == against->base) &&
@@ -177,27 +192,29 @@ uint32_t main(void) {
                   ;
                 current->next = against->next;
               }
-              clean = false;
+              dirty = true;
             }
-      } while (clean);
+      } while (dirty);
 
       have_mmap = true;
       break;
     }
     default:
-      put_sz("Ignoring multiboot tag 0x");
+      put_sz(": ignoring\n");
-      put_32_hex(tag_pointer->type);
-      put_char('\n');
 
     }
-    tag_pointer = (struct tag_start *)((uint32_t)tag_pointer + tag_pointer->size);
+    tag_pointer = (struct tag_start *)(((uint32_t)tag_pointer + tag_pointer->size - 1 & 0xfffffff8) + 8);
-  };
+  }
 
   if (!have_boot_device)
     return NO_BOOT_DEVICE;
   if (!have_mmap)
     return NO_MMAP;
 
+  put_sz("Halting.");
+  while (1)
+    ;
+
   if (!((proc_table = allocate_block(sizeof(struct proc_info) * 65536, KERNEL)) &&
         (file_table = allocate_block(sizeof(struct file_info) * 65536, KERNEL))))
     return INSUFF_MEMORY;
@@ -206,3 +223,11 @@ uint32_t main(void) {
   while (1)
     put_sz("|\b/\b-\b\\\b");
 }
+
+void wrapped_main(void) {
+  uint32_t error = main();
+  set_color(0x47);
+  clear();
+  put_sz("Error: 0x");
+  put_32_hex(error);
+}

src/kernel/serial.asm

@@ -0,0 +1,29 @@
+;Copyright 2019 Benji Dial
+
+;Permission to use, copy, modify, and/or distribute this
+;software for any purpose with or without fee is hereby
+;granted, provided that the above copyright notice and this
+;permission notice appear in all copies.
+
+;THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS
+;ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
+;IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
+;EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+;INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+;RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+;ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+;ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+;OF THIS SOFTWARE.
+
+global send_byte
+global read_byte
+
+section .text
+;COM1:   COM2:   COM3:   COM4:
+;0x03f8, 0x02f8, 0x03e8, 0x02e8
+
+send_byte:;void send_byte(uint8_t value, uint8_t port)
+  ;TODO
+
+read_byte:;uint8_t read_byte(uint8_t port)
+  ;TODO

src/kernel/serial.h

@@ -0,0 +1,38 @@
+/*
+Copyright 2019 Benji Dial
+
+Permission to use, copy, modify, and/or distribute this
+software for any purpose with or without fee is hereby
+granted, provided that the above copyright notice and this
+permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS
+ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
+EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+OF THIS SOFTWARE.
+*/
+
+#include <stdint.h>
+
+#ifndef SERIAL_H
+#define SERIAL_H
+
+enum serials {
+  COM1 = 0,
+  COM2 = 1,
+  COM3 = 2,
+  COM4 = 3
+};
+
+/*
+Commenting out so I don't accidentally call garbage while these are unimplemented.
+void send_byte(uint8_t value, uint8_t port);
+uint8_t read_byte(uint8_t port);
+*/
+
+#endif

src/kernel/stub.asm

@@ -15,7 +15,9 @@
 ;ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 ;OF THIS SOFTWARE.
 
-extern main
+global _start
+extern wrapped_main
+extern tag_pointer
 
 section .mb_header
 dd 0xe852_50d6;magic
@@ -34,37 +36,12 @@ mb_end:
 
 section .text
 bits 32
-global _start
 _start:
-  mov dword [info_pointer], ebx
+  add ebx, 8
+  mov dword [tag_pointer], ebx
   mov esp, stack
-  call main
-  mov edx, eax
 
-  mov eax, 0x4720_4720
+  call wrapped_main
-  mov ebx, 0x000b_8000
-  mov ecx, 0x000b_8fa0
-clear_screen_loop:
-  mov dword [ebx], eax
-  add ebx, 4
-  test ebx, ecx
-  jne clear_screen_loop
-
-  mov dword [0x000b_8000], 0x4772_4745
-  mov dword [0x000b_8004], 0x476f_4772
-  mov dword [0x000b_8008], 0x4720_4772
-
-  mov ebx, 0x000b_8020
-  mov ecx, 0x000b_800a
-error_number_loop:
-  mov al, dl
-  and al, 0x07
-  or al, 0x30
-  mov byte [ebx], al
-  sub ebx, 2
-  shr edx, 3
-  test ebx, ecx
-  jne error_number_loop
 
   cli
 halt:
@@ -72,7 +49,6 @@ halt:
   jmp halt
 
 section .bss
-global info_pointer
 info_pointer resd 1
 resb 0x1000 - $ + $$
 stack:

src/kernel/vga.c

@@ -18,6 +18,7 @@ OF THIS SOFTWARE.
 */
 
 #include "vga.h"
+#include "serial.h"
 #include <stdbool.h>
 
 uint16_t cursor_pos = 0;
@@ -25,18 +26,24 @@ uint8_t color = 0x70;
 #define cols 80
 #define rows 25
 
+void clear(void) {
+  uint32_t fill = 0x00200020 | (color << 24) | (color << 8);
+  for (uint32_t *i = (uint32_t *)VGA_BUFFER; i < (uint32_t *)(VGA_BUFFER + rows * cols * 2); ++i)
+    *i = fill;
+  cursor_pos = 0;
+}
+
 void scroll(void) {
   cursor_pos -= cols * 2;
-  uint32_t *limit = (uint32_t *)(VGA_BUFFER + cols * (rows - 1));
+  for (uint32_t *i = (uint32_t *)VGA_BUFFER; i < (uint32_t *)(VGA_BUFFER + (rows - 1) * cols * 2); ++i)
-  for (uint32_t *i = (uint32_t *)VGA_BUFFER; i < limit; ++i)
     *i = *(i + cols / 2);
-  limit += cols / 2;
+  uint32_t fill = (color << 8) | (color << 24) | 0x00200020;
-  uint32_t fill = (color * 0x0100 + (uint8_t)' ') * 0x00010001;
+  for (uint32_t *i = (uint32_t *)(VGA_BUFFER + (rows - 1) * cols * 2); i < (uint32_t *)(VGA_BUFFER + rows * cols * 2); ++i)
-  for (uint32_t *i = limit - cols / 2; i < limit; ++i)
     *i = fill;
 }
 
 void put_char(uint8_t ch) {
+  //send_byte(ch, COM2);
   switch (ch) {
   case '\b':
     if (cursor_pos)
@@ -89,12 +96,12 @@ void put_16(uint16_t n) {
 
 void put_32_hex(uint32_t n) {
   for (uint8_t i = 0; i < 4; ++i) {
-    put_char(n / 0xf0000000 + (n < 0xa0000000 ? (uint8_t)'0' : (uint8_t)'a' - 1));
+    put_char("0123456789abcdef"[n >> 28]);
     n <<= 4;
   }
-  put_char('_');
+  put_char('.');
   for (uint8_t i = 0; i < 4; ++i) {
-    put_char(n / 0xf0000000 + (n < 0xa0000000 ? (uint8_t)'0' : (uint8_t)'a' - 1));
+    put_char("0123456789abcdef"[n >> 28]);
     n <<= 4;
   }
 }

src/kernel/vga.h

@@ -22,7 +22,13 @@ OF THIS SOFTWARE.
 #ifndef VGA_H
 #define VGA_H
 
+#define put_debug(name, value) \
+  put_sz(name ": 0x"); \
+  put_32_hex(value); \
+  put_char('\n');
+
 #define VGA_BUFFER ((uint8_t *)0x000b8000)
+void clear(void);
 void put_char(uint8_t ch);
 void put_sz(uint8_t *s);
 void put_16(uint16_t n);