fixes in vga.c setting the hardware cursor correctly

reading VGA hardware cursor from stage2 in boot loader for last messages

4 files changed, 44 insertions, 6 deletions

diff --git a/src/boot.asm b/src/boot.asm
index 377ec66..3257a56 100644
--- a/src/boot.asm
+++ b/src/boot.asm
@@ -118,6 +118,9 @@ BEGIN_PROTECTED_MODE:
 ; call our kernel
 	call c_entry
 
+; restore cursor variables from VGA hardware
+	call read_hardware_vga_cursor
+
 ; "kernel halted" message, when we terminate the C kernel
 HALT_OS:
 	mov si, MESSAGE_HALTED
diff --git a/src/kernel.c b/src/kernel.c
index 61281e9..5021813 100644
--- a/src/kernel.c
+++ b/src/kernel.c
@@ -28,12 +28,12 @@ void entry( void )
 			x_pos++;
 		}
 		vga_put_char_at( &vga, x_pos, y_pos, bar[i%4] );
-		for( int j = 0; j < 1500; j++ ) {
+		for( int j = 0; j < 150; j++ ) {
 		}
 	}
 	vga_put_char_at( &vga, x_pos, y_pos, '.' );	
 	vga_put_newline( &vga );
-	   
+		   
 	//~ vga_set_color( &vga, VGA_COLOR_WHITE );
 	//~ vga_set_background_color( &vga, VGA_COLOR_RED );
 	//~ vga_clear_screen( &vga );
diff --git a/src/stage2_functions.asm b/src/stage2_functions.asm
index 11a77c0..2954d62 100644
--- a/src/stage2_functions.asm
+++ b/src/stage2_functions.asm
@@ -137,6 +137,38 @@ update_vga_cursor:
 	pop eax
 	ret
 
+; read cursor from hardware
+read_hardware_vga_cursor:
+	push eax
+	push ebx
+	push ecx
+	push edx
+	xor eax, eax
+	xor ebx, ebx
+	mov al, 0eh
+	mov dx, 3d4h
+	out dx, al
+	mov dx, 3d5h
+	in al, dx
+	mov bh, al
+	mov al, 0fh
+	mov dx, 3d4h
+	out dx, al
+	mov dx, 3d5h
+	in al, dx
+	mov bl, al
+	mov ax, bx
+	mov edx, 0
+	mov cx, VIDEO_COLS
+	div cx
+	mov [CURSOR_X], dx
+	mov [CURSOR_Y], ax 
+	pop edx
+	pop ecx
+	pop ebx
+	pop eax
+	ret
+
 ; check whether the end of the loaded image contains in fact the magic
 ; string (avoid truncation of image)
 check_magic:
diff --git a/src/vga.c b/src/vga.c
index daad532..498bb20 100644
--- a/src/vga.c
+++ b/src/vga.c
@@ -19,6 +19,8 @@ void vga_init( vga_t *vga )
 	vga->color = VGA_COLOR_DARK_GREY;
 	vga->background_color = VGA_COLOR_BLACK;
 
+	// make sure we use the 0x3dx VGA ports, is done
+	// in assembly in stage 2 too
 	port8_init( &vga->crtc_misc_port, 0x3d2 );
 	port8_write( &vga->crtc_misc_port, 1 );
 
@@ -54,10 +56,7 @@ void vga_set_cursor( vga_t *vga, const int x, const int y )
 }
 
 void vga_set_cursor_from_hardware( vga_t *vga )
-{	
-	vga->cursor_x = 0;
-	vga->cursor_y = 0;
-	
+{
 	uint16_t hw_cursor_pos;
 	
 	port8_write( &vga->crtc_index_port, 14 );
@@ -176,6 +175,8 @@ void vga_put_char( vga_t *vga, const char c )
 			scroll_screen( vga );
 		}
 	}
+
+	vga_set_cursor_on_hardware( vga );
 }
 
 void vga_put_string( vga_t *vga, const char *s )
@@ -201,6 +202,8 @@ void vga_put_newline( vga_t *vga )
 	if( vga->cursor_y >= vga->res_y ) {
 		scroll_screen( vga );
 	}
+
+	vga_set_cursor_on_hardware( vga );
 }