From 1fc1c0150cad87e55628e578943db1f2c72feac6 Mon Sep 17 00:00:00 2001
From: Quinten Kock <quinten@quinten.space>
Date: Mon, 30 Nov 2020 02:56:55 +0100
Subject: [PATCH] Reorganize kernel code

---
 kernel/Makefile             |  2 +-
 kernel/src/entry-stivale2.c | 28 ++++++++++++++++++++
 kernel/src/main-stivale2.c  | 51 -------------------------------------
 kernel/src/main.c           |  7 +++++
 kernel/src/main.h           |  1 +
 kernel/src/vga.c            | 20 +++++++++++++++
 kernel/src/vga.h            | 19 ++++++++++++++
 7 files changed, 76 insertions(+), 52 deletions(-)
 create mode 100644 kernel/src/entry-stivale2.c
 delete mode 100644 kernel/src/main-stivale2.c
 create mode 100644 kernel/src/main.c
 create mode 100644 kernel/src/main.h
 create mode 100644 kernel/src/vga.c
 create mode 100644 kernel/src/vga.h

diff --git a/kernel/Makefile b/kernel/Makefile
index 2273354..4a3eab5 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -6,7 +6,7 @@ LD              = ld -m elf_x86_64
 QEMU            = qemu-system-x86_64
 QEMUFLAGS       = -m 1G -enable-kvm -cpu host
 LDINTERNALFLAGS := -Tlinker.ld 
-INTERNALCFLAGS  := -I../ext/limine/stivale \
+INTERNALCFLAGS  := -I../ext/limine/stivale -mcmodel=kernel
 
 CFILES    := $(shell find src -type f -name '*.c')
 HFILES    := $(shell find src -type f -name '*.h')
diff --git a/kernel/src/entry-stivale2.c b/kernel/src/entry-stivale2.c
new file mode 100644
index 0000000..f1eeb1c
--- /dev/null
+++ b/kernel/src/entry-stivale2.c
@@ -0,0 +1,28 @@
+#include <stivale2.h>
+#include <stdint.h>
+#include <stddef.h>
+
+#include "main.h"
+
+static uint8_t stack[4096] = {0};
+void stivale2_main(struct stivale2_struct *info);
+
+struct stivale2_header_tag_smp smp_request = {
+    .tag = {
+        .identifier = STIVALE2_HEADER_TAG_SMP_ID,
+        .next       = 0
+    },
+    .flags = 0
+};
+
+__attribute__((section(".stivale2hdr"), used))
+struct stivale2_header header2 = {
+    .entry_point = (uint64_t)stivale2_main,
+    .stack       = (uintptr_t)stack + sizeof(stack),
+    .flags       = 0,
+    .tags        = (uint64_t)&smp_request
+};
+
+void stivale2_main(struct stivale2_struct *info) {
+	kmain();
+}
diff --git a/kernel/src/main-stivale2.c b/kernel/src/main-stivale2.c
deleted file mode 100644
index de225f0..0000000
--- a/kernel/src/main-stivale2.c
+++ /dev/null
@@ -1,51 +0,0 @@
-#include <stivale2.h>
-#include <stdint.h>
-#include <stddef.h>
-
-#define VGA_ADDRESS 0xb8000
-#define VGA_COLOR(character, color) ((uint16_t) (character) | (uint16_t) (color) << 8)
-#define VGA_BLACK        0
-#define VGA_BLUE         1
-#define VGA_GREEN        2
-#define VGA_CYAN         3
-#define VGA_RED          4
-#define VGA_PURPLE       5
-#define VGA_BROWN        6
-#define VGA_GRAY         7
-#define VGA_DARK_GRAY    8
-#define VGA_LIGHT_BLUE   9
-#define VGA_LIGH_GREEN   10
-#define VGA_LIGHT_CYAN   11
-#define VGA_LIGHT_RED    12
-#define VGA_LIGHT_PURPLE 13
-#define VGA_YELLOW       14
-#define VGA_WHITE        15
-
-static uint8_t stack[4096] = {0};
-void stivale2_main(struct stivale2_struct *info);
-
-struct stivale2_header_tag_smp smp_request = {
-    .tag = {
-        .identifier = STIVALE2_HEADER_TAG_SMP_ID,
-        .next       = 0
-    },
-    .flags = 0
-};
-
-__attribute__((section(".stivale2hdr"), used))
-struct stivale2_header header2 = {
-    .entry_point = (uint64_t)stivale2_main,
-    .stack       = (uintptr_t)stack + sizeof(stack),
-    .flags       = 0,
-    .tags        = (uint64_t)&smp_request
-};
-
-void stivale2_main(struct stivale2_struct *info) {
-    volatile uint16_t *vga_buffer = (uint16_t*)VGA_ADDRESS;
-    vga_buffer[0] = VGA_COLOR('h', VGA_GREEN);
-    vga_buffer[1] = VGA_COLOR('e', VGA_GREEN);
-    vga_buffer[2] = VGA_COLOR('l', VGA_GREEN);
-    vga_buffer[3] = VGA_COLOR('l', VGA_GREEN);
-    vga_buffer[4] = VGA_COLOR('o', VGA_GREEN);
-    asm volatile ("hlt");
-}
diff --git a/kernel/src/main.c b/kernel/src/main.c
new file mode 100644
index 0000000..e4c02ff
--- /dev/null
+++ b/kernel/src/main.c
@@ -0,0 +1,7 @@
+#include "vga.h"
+
+void kmain() {
+	vga_puts("hello!");
+	vga_putc('h');
+	asm volatile ("hlt");
+}
diff --git a/kernel/src/main.h b/kernel/src/main.h
new file mode 100644
index 0000000..a79acd1
--- /dev/null
+++ b/kernel/src/main.h
@@ -0,0 +1 @@
+void kmain();
diff --git a/kernel/src/vga.c b/kernel/src/vga.c
new file mode 100644
index 0000000..9ad8d48
--- /dev/null
+++ b/kernel/src/vga.c
@@ -0,0 +1,20 @@
+#include <stdint.h>
+
+#include "vga.h"
+
+#define VGA_ADDRESS 0xb8000
+
+static uint8_t current_color = VGA_WHITE;
+uint16_t *vga_buffer = (uint16_t*)VGA_ADDRESS;
+
+void vga_putc(char c) {
+	*(vga_buffer++) = (uint16_t)c | (uint16_t)(current_color) << 8;
+}
+
+void vga_puts(char *c) {
+	char cur = *(c++);
+	while(cur != '\0') {
+		vga_putc(cur);
+		cur = *(c++);
+	}
+}
diff --git a/kernel/src/vga.h b/kernel/src/vga.h
new file mode 100644
index 0000000..213de43
--- /dev/null
+++ b/kernel/src/vga.h
@@ -0,0 +1,19 @@
+#define VGA_BLACK        0
+#define VGA_BLUE         1
+#define VGA_GREEN        2
+#define VGA_CYAN         3
+#define VGA_RED          4
+#define VGA_PURPLE       5
+#define VGA_BROWN        6
+#define VGA_GRAY         7
+#define VGA_DARK_GRAY    8
+#define VGA_LIGHT_BLUE   9
+#define VGA_LIGH_GREEN   10
+#define VGA_LIGHT_CYAN   11
+#define VGA_LIGHT_RED    12
+#define VGA_LIGHT_PURPLE 13
+#define VGA_YELLOW       14
+#define VGA_WHITE        15
+
+void vga_putc(char c);
+void vga_puts(char *c);