program loading, others

big kernel additions: paging, elf loading, separate kernel and user page allocation
it now properly loads and runs sd0:bin/init.elf
still need to determine which disk was booted from, and start the init on that disk

1 files changed, 7 insertions, 10 deletions

diff --git a/src/kernel/vga.c b/src/kernel/vga.c
index 7506416..c03e5f0 100644
--- a/src/kernel/vga.c
+++ b/src/kernel/vga.c
@@ -2,9 +2,8 @@
 #include <stdint.h>
 
 #define VGA_COLUMNS 80
-#define VGA_LINES 25
 #define VGA_START (uint16_t *)0x000b8000
-#define VGA_END (VGA_START + VGA_COLUMNS * VGA_LINES)
+#define VGA_END (VGA_START + VGA_COLUMNS * 25)
 static uint16_t *cursor = VGA_START;
 static uint16_t mask;
 
@@ -12,12 +11,12 @@ void vga_set_color(uint8_t new_color) {
   mask = new_color << 8;
 }
 
-void vga_scroll() {
+static void vga_scroll() {
   for (uint32_t *i = (uint32_t *)VGA_START; i < (uint32_t *)(VGA_END - VGA_COLUMNS); ++i)
     *i = *(i + VGA_COLUMNS / 2);
   uint32_t f = (mask | (uint8_t)' ') * 0x00010001;
   for (uint32_t *i = (uint32_t *)(VGA_END - VGA_COLUMNS); i < (uint32_t *)VGA_END; ++i)
-    *i++ = f;
+    *i = f;
   cursor -= VGA_COLUMNS;
 }
 
@@ -30,12 +29,10 @@ void vga_blank() {
 }
 
 void vga_printch(char ch) {
-  if (ch == '\n') {
-    if ((cursor = cursor - (cursor - VGA_START) % VGA_COLUMNS + VGA_COLUMNS) == VGA_END)
-      vga_scroll();
-    return;
-  }
-  *cursor++ = mask | (uint8_t)ch;
+  if (ch == '\n')
+    cursor = ((cursor - VGA_START) / VGA_COLUMNS + 1) * VGA_COLUMNS + VGA_START;
+  else
+    *cursor++ = mask | (uint8_t)ch;
   if (cursor == VGA_END)
     vga_scroll();
 }
\ No newline at end of file