Rejigger cga and some console code.

e2fb4373 · Silas Boyd-Wickizer · 69d390f1 · e2fb4373 · e2fb4373 · e2fb4373
--- a/boot.S
+++ b/boot.S
@@ -74,9 +74,6 @@ start:

 	# Initialize stack.
 	movl $PADDR(stack+STACK), %esp
-
-	# Initialize screen.
-	call initscreen
 	
 	# Check for page size extensions.
 	movl $1, %eax
@@ -192,47 +189,6 @@ bootpanic:
 	movb %bl, (%esi)
 	jmp 2b

-initscreen:
-	pushal
-
-	# Initialize screen.
-	# 25 lines of white on black.
-	cld
-	movl $CGATEXTMEM, %edi
-	movl $0x0f20, %eax
-	movl $(80*25), %ecx
-	rep stosw
-
-	# Hide cursor at beginning of first line.
-	movw $0, %di
-	call setcursor
-
-	popal
-	ret
-
-.globl setcursor
-setcursor:
-	pushl %edx
-	pushl %eax
-	pushl %ebx
-	movl %edi, %ebx
-	movw $0x3d4, %dx
-	movw $14, %ax
-	outb %al, %dx
-	movw $0x3d5, %dx
-	movb %bh, %al
-	outb %al, %dx
-	movw $0x3d4, %dx
-	movw $15, %ax
-	outb %al, %dx
-	movw $0x3d5, %dx
-	movb %bl, %al
-	outb %al, %dx
-	popl %ebx
-	popl %eax
-	popl %edx
-	ret
-
 # Initial stack
 .comm stack, STACK


--- a/cga.c
+++ b/cga.c
 #include "types.h"
 #include "kernel.h"
+#include "x86.h"

-static volatile u16 *screen = (u16*)(KBASE+0xb8000);
+#define BACKSPACE 0x100
+#define CRTPORT 0x3d4
+static volatile u16 *crt = (u16*)(KBASE + 0xb8000);  // CGA memory
 // Black background, (high intensity) white foreground
 static int color = ((0 << 4) | 15) << 8;
-static int cursor;
-
-extern void setcursor(int);
-
-static void
-cgaputs(const char *s)
-{
-  uint8 *p, *ep;
-
-  p = (uint8*)s;
-  ep = p+strlen(s);
-
-  for (; p < ep; p++)
-    cgaputc(*p);
-}

 void
-cgaputc(char c)
+cgaputc(int c)
 {
-  int i;
-
-  if(c == '\n') {
-    cursor += 80 - cursor%80;
-  } else {
-    screen[cursor] = color | c;
-    cursor++;
-  }
-  if(cursor == 25*80) {
-    memmove((void*)screen+80*2, (void*)screen+80*3, 80*(25-3)*2);
-    for(i=0; i<80; i++)
-      screen[(24*80+i)] = color | (' ' & 0xff);
-    cursor -= 80;
+  int pos;
+  
+  // Cursor position: col + 80*row.
+  outb(CRTPORT, 14);
+  pos = inb(CRTPORT+1) << 8;
+  outb(CRTPORT, 15);
+  pos |= inb(CRTPORT+1);
+
+  if(c == '\n')
+    pos += 80 - pos%80;
+  else if(c == BACKSPACE){
+    if(pos > 0) --pos;
+  } else
+    crt[pos++] = (c&0xff) | color;
+  
+  if((pos/80) >= 24){  // Scroll up.
+    memmove((void*)crt, (void*)crt+80, sizeof(crt[0])*23*80);
+    pos -= 80;
+    memset((void*)crt+pos, 0, sizeof(crt[0])*(24*80 - pos));
  }
+  
+  outb(CRTPORT, 14);
+  outb(CRTPORT+1, pos>>8);
+  outb(CRTPORT, 15);
+  outb(CRTPORT+1, pos);
+  crt[pos] = ' ' | 0x0700;
 }

 void
 initcga(void)
 {
-  // Assume boot.S set up the screen.
-  // We're just taking over the cursor position.
-  cursor = 2*80;
-  setcursor(cursor);
-  
-  cgaputs("cga...\n");
-  setcursor(cursor);
+  char *p;
+  int i;
+
+  for (i = 0; i < 80*25; i++)
+    crt[i] = 0x0f20;
+
+  outb(CRTPORT, 14);
+  outb(CRTPORT+1, 0);
+  outb(CRTPORT, 15);
+  outb(CRTPORT+1, 0);
+
+  // Announce that we're here.
+  for(p="cga..\n"; *p; p++)
+    cgaputc(*p);
 }
--- a/kernel.h
+++ b/kernel.h
@@ -36,7 +36,7 @@ void            brelse(struct buf*, int writer);
 void            bwrite(struct buf*);

 // cga.c
-void            cgaputc(char c);
+void            cgaputc(int c);

 // condvar.c
 void            initcondvar(struct condvar *, char *);

--- a/uart.c
+++ b/uart.c
@@ -39,7 +39,7 @@ uartintr(void)
 void
 inituart(void)
 {
-    char *p;
+  char *p;

  // Turn off the FIFO
  outb(COM1+2, 0);
@@ -65,6 +65,6 @@ inituart(void)
  ioapicenable(IRQ_COM1, 0);

  // Announce that we're here.
-  for(p="uart...\n"; *p; p++)
+  for(p="uart..\n"; *p; p++)
    uartputc(*p);
 }