Implemented initial printk. Added multiboot support.

Makefile

@@ -5,7 +5,7 @@ GNU	?= $(PREFIX)/$(ARCH)/bin/$(ARCH)
 
 # Source files
 SOURCES_ASM	:= arch/$(ARCH)/boot.s
-SOURCES_C	:= driver/video/vga.c kernel/brados.c lib/string.c
+SOURCES_C	:= arch/$(ARCH)/multiboot.c driver/video/vga.c kernel/brados.c kernel/printk.c lib/string.c
 
 # Object files
 OBJS	:= $(patsubst %.s,%.o,$(SOURCES_ASM))

arch/arm-none-eabi/multiboot.c

@@ -0,0 +1,13 @@
+#include <stdint.h>
+
+#include <multiboot.h>
+
+uint32_t multiboot_getAddress()
+{
+	return 0;
+}
+
+uint32_t multiboot_getMagic()
+{
+	return 0;
+}

arch/i586-elf/boot.s

@@ -27,6 +27,9 @@ _start:
 	# Setup the stack
 	movl $stack_top, %esp
 	
+	# Push the multiboot information onto the stack
+	push %ebx
+	push %eax
 	# Call the main kernel function
 	call brados_main
 	

arch/i586-elf/multiboot.c

@@ -0,0 +1,23 @@
+#include <stdint.h>
+
+#include <multiboot.h>
+
+uint32_t multiboot_getAddress()
+{
+	uint32_t address = 0;
+	__asm__(
+		"movl %%ebx, %0;"
+		:"=r"(address)
+	);
+	return address;
+}
+
+uint32_t multiboot_getMagic()
+{
+	uint32_t magic = 0;
+	__asm__(
+		"movl %%eax, %0;"
+		:"=r"(magic)
+	);
+	return magic;
+}

driver/video/vga.c

@@ -82,6 +82,26 @@ void term_setColor(struct vgastate *state, uint8_t color)
 	state->term_color = color;
 }
 
+// Test various VGA functionality
+void term_test(struct vgastate *term)
+{
+	// Test line wrapping
+	term_writeStr(term, "Welcome to the desert of the real. I thought what I'd do was I'd pretend I was one of those deaf mutes.\n\n");
+	
+	// Test colors
+	term_setColor(term, make_color(VGA_COLOR_BLACK, VGA_COLOR_WHITE));
+	term_writeStr(term, "This text should be inverse.\n");
+	term_setColor(term, make_color(VGA_COLOR_LIGHT_BLUE, VGA_COLOR_GREEN));
+	term_writeStr(term, "This text should be colorful.\n\n");
+	
+	// Test scrolling
+	term_setColor(term, make_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK));
+	for (size_t i = 0; i < 20; i++) {
+		term_writeStr(term, "Printing some lines.\n");
+		for (volatile size_t j = 0; j < 100000000; j++);
+	}
+}
+
 // Write a string to a VGA term
 void term_writeStr(struct vgastate *state, const char *data)
 {

include/brados/printk.h

@@ -0,0 +1,8 @@
+#ifndef __brados_printk_h__
+#define __brados_printk_h__
+
+#include <video/vga.h>
+
+int printk(struct vgastate *term, const char *fmt, ...);
+
+#endif

include/brados/string.h

@@ -3,6 +3,7 @@
 
 #include <stddef.h>
 
+int strindexof(char c, const char *str);
 size_t strlen(const char *str);
 
 #endif

include/multiboot.h

@@ -0,0 +1,79 @@
+#ifndef __brados_multiboot_h__
+#define __brados_multiboot_h__
+
+#include <stdint.h>
+
+// For more information on this structure, see:
+// http://www.gnu.org/software/grub/manual/multiboot/multiboot.html
+struct multiboot_header {
+	// Indicates the presence and validity of other fields
+	uint32_t flags;
+	
+	// Present if bit 0 in 'flags' is set
+	uint32_t mem_lower;
+	uint32_t mem_upper;
+	
+	// Present if bit 1 in 'flags' is set
+	uint32_t boot_device;
+	
+	// Present if bit 2 in 'flags' is set
+	uint32_t cmdline;
+	
+	// Present if bit 3 in 'flags' is set
+	uint32_t mods_count;
+	uint32_t mods_addr;
+	
+	// Present if bits 4 or 5 are present in 'flags'
+	// NOTE: Bits 4 and 5 are mutually exclusive. Bit 4 indicates fields
+	// related to a.out kernel images, while bit 5 indicated fields related
+	// to ELF kernel images. Since BRaDOS is an ELF kernel, the bit 5 field
+	// names will be used.
+	uint32_t shdr_num;	// "tabsize" for an a.out kernel
+	uint32_t shdr_size;	// "strsize" for an a.out kernel
+	uint32_t shdr_addr;	// "addr" for an a.out kernel
+	uint32_t shdr_shndx;	// "reserved" for an a.out kernel
+	
+	// Present if bit 6 in 'flags' is set
+	uint32_t mmap_length;
+	uint32_t mmap_addr;
+	
+	// Present if bit 7 in 'flags' is set
+	uint32_t drives_length;
+	uint32_t drives_addr;
+	
+	// Present if bit 8 in 'flags' is set
+	uint32_t config_table;
+	
+	// Present if bit 9 in 'flags' is set
+	uint32_t boot_loader_name;
+	
+	// Present if bit 10 in 'flags' is set
+	uint32_t apm_table;
+	
+	// Present if bit 11 in 'flags' is set
+	uint32_t vbe_control_info;
+	uint32_t vbe_mode_info;
+	uint16_t vbe_mode;
+	uint16_t vbe_interface_seg;
+	uint16_t vbe_interface_off;
+	uint16_t vbe_interface_len;
+};
+
+struct multiboot_mmap {
+	uint32_t size;
+	uint64_t base_addr;
+	uint64_t length;
+	uint32_t type;
+};
+
+struct multiboot_mod {
+	uint32_t mod_start;
+	uint32_t mod_end;
+	uint32_t string;
+	uint32_t reserved;
+};
+
+uint32_t multiboot_getAddress();
+uint32_t multiboot_getMagic();
+
+#endif

include/video/vga.h

@@ -37,28 +37,14 @@ enum vga_color
 	VGA_COLOR_WHITE = 15
 };
 
-// Create a VGA color
 uint8_t make_color(enum vga_color fg, enum vga_color bg);
-
-// Create a VGA character
 uint16_t make_vgaEntry(char c, uint8_t color);
-
-// Initialize a VGA term
 void term_init(struct vgastate *state);
-
-// Write a character to a VGA term
 void term_putChar(struct vgastate *state, char c);
-
-// Place a character in a VGA term's buffer
 void term_putEntryAt(struct vgastate *state, char c, uint8_t color, size_t x, size_t y);
-
-// Scroll the term down 1 line
 void term_scroll(struct vgastate *state);
-
-// Set VGA term color
 void term_setColor(struct vgastate *state, uint8_t color);
-
-// Write a string to a VGA term
+void term_test(struct vgastate *term);
 void term_writeStr(struct vgastate *state, const char *data);
 
 #endif

kernel/brados.c

@@ -1,36 +1,20 @@
 #include <stddef.h>
+#include <stdint.h>
 
+#include <brados/printk.h>
 #include <brados/string.h>
 #include <video/vga.h>
+#include <multiboot.h>
 
 // Make sure we are using the right compiler
 #if defined(__linux__)
 #error "You are using the wrong compiler."
 #endif
 
-// Test various VGA functionality
-void vgaTests(struct vgastate *term)
-{
-	// Test line wrapping
-	term_writeStr(term, "Welcome to the desert of the real. I thought what I'd do was I'd pretend I was one of those deaf mutes.\n\n");
-	
-	// Test colors
-	term_setColor(term, make_color(VGA_COLOR_BLACK, VGA_COLOR_WHITE));
-	term_writeStr(term, "This text should be inverse.\n");
-	term_setColor(term, make_color(VGA_COLOR_LIGHT_BLUE, VGA_COLOR_GREEN));
-	term_writeStr(term, "This text should be colorful.\n\n");
-	
-	// Test scrolling
-	term_setColor(term, make_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK));
-	for (size_t i = 0; i < 20; i++) {
-		term_writeStr(term, "Printing some lines.\n");
-		for (volatile size_t j = 0; j < 100000000; j++);
-	}
-}
-
 // Main kernel function
-void brados_main()
+void brados_main(uint32_t multiMagic, uint32_t multiAddr)
 {
+	// Initialize VGA terminal
 	struct vgastate term;
 	term_init(&term);
 	
@@ -38,7 +22,21 @@ void brados_main()
 	term_writeStr(&term, "Welcome to BRaDOS!\n");
 	term_writeStr(&term, "written by L. Bradley LaBoon\n\n");
 	
-	vgaTests(&term);
+	// VGA tests
+	//term_test(&term);
 	
+	// Get multiboot info
+	printk(&term, "Multiboot value: %x\n", multiMagic);
+	if (multiMagic != 0x2BADB002) {
+		term_writeStr(&term, "Error! Multiboot header not present. Quitting.\n");
+		return;
+	}
+	printk(&term, "Multiboot address: %x\n", multiAddr);
+	struct multiboot_header *multiHead = (struct multiboot_header *) multiAddr;
+	printk(&term, "Flags: %x\nMem Lower: %x\nMem Upper: %x\n", multiHead->flags, multiHead->mem_lower, multiHead->mem_upper);
+	char *bootName = (char *) multiHead->boot_loader_name;
+	printk(&term, "Boot loader: %s\n\n", bootName);
+	
+	// Done
 	term_writeStr(&term, "Done.");
 }

kernel/printk.c

@@ -0,0 +1,76 @@
+#include <stdarg.h>
+#include <stddef.h>
+
+#include <brados/printk.h>
+#include <brados/string.h>
+#include <video/vga.h>
+
+const char *BASE16 = "0123456789ABCDEF";
+
+static int printNum(struct vgastate *term, unsigned int num, unsigned int base)
+{
+	int numPrinted = 0;
+	int digit = num % base;
+	if (num >= base)
+		numPrinted += printNum(term, num / base, base);
+	term_putChar(term, BASE16[digit]);
+	numPrinted++;
+	return numPrinted;
+}
+
+int printk(struct vgastate *term, const char *fmt, ...)
+{
+	int numPrinted = 0;
+	va_list args;
+	va_start(args, fmt);
+	
+	for (size_t i = 0; i < strlen(fmt); i++) {
+		if (fmt[i] == '%') {
+			int d;
+			unsigned int x;
+			char *s;
+			switch (fmt[i+1]) {
+			case '%':
+				term_putChar(term, '%');
+				numPrinted++;
+				break;
+			case 'c':
+				term_putChar(term, (char) va_arg(args, int));
+				numPrinted++;
+				break;
+			case 'i':
+				d = va_arg(args, int);
+				if (d < 0) {
+					term_putChar(term, '-');
+					numPrinted++;
+					d *= -1;
+				}
+				numPrinted += printNum(term, (unsigned int) d, 10);
+				break;
+			case 's':
+				s = va_arg(args, char *);
+				term_writeStr(term, s);
+				numPrinted += strlen(s);
+				break;
+			case 'x':
+				x = va_arg(args, unsigned int);
+				term_writeStr(term, "0x");
+				numPrinted += 2;
+				numPrinted += printNum(term, x, 16);
+				break;
+			default:
+				term_putChar(term, fmt[i+1]);
+				numPrinted++;
+				break;
+			}
+			
+			i++;
+		} else {
+			term_putChar(term, fmt[i]);
+			numPrinted++;
+		}
+	}
+	
+	va_end(args);
+	return numPrinted;
+}

lib/string.c

@@ -2,6 +2,18 @@
 
 #include <brados/string.h>
 
+// Find the first instance of c in str
+// Returns -1 if c is not found
+int strindexof(char c, const char *str)
+{
+	for (size_t i = 0; i < strlen(str); i++) {
+		if (str[i] == c)
+			return i;
+	}
+	
+	return -1;
+}
+
 // Find the length of a string
 size_t strlen(const char *str)
 {