From d6b64c65a0d09dba96a65edd2959bd58fe781fcc Mon Sep 17 00:00:00 2001
From: Andreas Baumann <mail@andreasbaumann.cc>
Date: Sun, 14 May 2017 19:20:38 +0200
Subject: some small fixes, clang image overload (magic doesn't work, most
 likely because memory is not wiped between qemu invocations)

---
 DESIGN                   | 12 ++++++++++++
 doc/README.Tyndur        |  2 ++
 src/Makefile             |  4 ++--
 src/console.c            | 16 ++++++++++------
 src/kernel.c             |  6 +++++-
 src/stage1_functions.asm |  2 +-
 6 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/DESIGN b/DESIGN
index b7ba1e2..b9a899b 100644
--- a/DESIGN
+++ b/DESIGN
@@ -1,11 +1,22 @@
 design principles
 -----------------
 
+The final goal is a self-hosting, self-compiling system, so we will
+have to implement or port the assember, the C compiler, a linker and
+a make program into the new operating system. So featuritis and
+non-standards will kill the project fast!
+
 Use strict ANSI C99. This means no inline-assembly. This means
 we have to write assembly routines if we need things not available
 in C (lgdt, in, out, etc.).
+Use the cdecl calling convetion when calling assembly from C.
+Stick to NASM assembly bare features (equ, org). Use only the absolute
+minimum.
 
 Make sure it compiles with every ANSI C99 compiler (gcc, clang, tcc, ...).
+Use only what is needed, nothing fancy.
+Try to compile as often as possible with different compilers on different
+host systems.
 
 Use only very simple makefile rules. Make sure we could also just
 use a simple shell script to compile the kernel.
@@ -13,3 +24,4 @@ use a simple shell script to compile the kernel.
 Avoid implementation and using of unsafe C functions. Provide safe
 counterparts wherever possible. There are of course exceptions like
 scrolling the VGA buffer with a memmove.
+
diff --git a/doc/README.Tyndur b/doc/README.Tyndur
index 26fd0a3..6e9b644 100644
--- a/doc/README.Tyndur
+++ b/doc/README.Tyndur
@@ -1,2 +1,4 @@
 http://www.lowlevel.eu/wiki/Týndur/Entwicklung
 git clone git://git.tyndur.org/tyndur.git
+
+inspired by console.c: especially the idea of having output to VGA and serial
diff --git a/src/Makefile b/src/Makefile
index 52a628b..c2b91fa 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -11,8 +11,8 @@ image.bin: boot.bin kernel.bin magic.bin
 	# + M * 512 (M is currently 7) = 3144 for kernel.bin
 	# + 1 * 512 = 512 for magic.bin
 	# (M + N + 1 is the number of sectors to be read in stage 2, as stage 1
-	# loads only the first sector, so adapt NOF_LOAD_SECTORS to 10)
-	truncate -s 5632 image.tmp
+	# loads only the first sector, so adapt NOF_LOAD_SECTORS to 12)
+	truncate -s 6656 image.tmp
 	cat image.tmp magic.bin > image.bin
 	
 boot.bin: boot.asm gdt.asm stage1_functions.asm stage2_functions.asm switch_mode.asm
diff --git a/src/console.c b/src/console.c
index d9ae941..ef4c36f 100644
--- a/src/console.c
+++ b/src/console.c
@@ -1,10 +1,14 @@
 #include "console.h"
 
 #include "string.h"
+#include "stddef.h"
 
 void console_init( console_t *console )
 {
 	memset( console, 0, sizeof( console_t ) );
+	
+	console->vga = NULL;
+	console->serial = NULL;
 }
 
 void console_add_vga_output( console_t *console, vga_t *vga )
@@ -19,33 +23,33 @@ void console_add_serial_output( console_t *console, serial_t *serial )
 
 void console_put_char( console_t *console, const char c )
 {
-	if( console->vga ) {
+	if( console->vga != NULL ) {
 		vga_put_char( console->vga, c );
 	}
 	
-	if( console->serial ) {
+	if( console->serial != NULL ) {
 		serial_put_char( console->serial, c );
 	}
 }
 
 void console_put_string( console_t *console, const char *s )
 {
-	if( console->vga ) {
+	if( console->vga != NULL ) {
 		vga_put_string( console->vga, s );
 	}
 	
-	if( console->serial ) {
+	if( console->serial != NULL ) {
 		serial_put_string( console->serial, s );
 	}
 }
 
 void console_put_newline( console_t *console )
 {
-	if( console->vga ) {
+	if( console->vga != NULL ) {
 		vga_put_newline( console->vga );
 	}
 	
-	if( console->serial ) {
+	if( console->serial != NULL ) {
 		serial_put_newline( console->serial );
 	}
 }
diff --git a/src/kernel.c b/src/kernel.c
index 91546a6..2cbe40a 100644
--- a/src/kernel.c
+++ b/src/kernel.c
@@ -38,8 +38,12 @@ void entry( void )
 	}
 	vga_put_char_at( &vga, x_pos, y_pos, '.' );	
 	serial_put_char( &serial, '.' );
-	console_put_newline( &console );
 	
+	console_put_newline( &console );
+
+	console_put_string( &console, "Terminating" );
+	console_put_newline( &console );
+		   
 	//~ vga_set_color( &vga, VGA_COLOR_WHITE );
 	//~ vga_set_background_color( &vga, VGA_COLOR_RED );
 	//~ vga_clear_screen( &vga );
diff --git a/src/stage1_functions.asm b/src/stage1_functions.asm
index c43da4d..854b3b4 100644
--- a/src/stage1_functions.asm
+++ b/src/stage1_functions.asm
@@ -2,7 +2,7 @@
 ; 3 * 512 for bootloader stage2 and the kernel code 
 ; (note: the first sector gets loaded by the BIOS, so
 ; subtract 1 here!)
-NOF_LOAD_SECTORS equ 11
+NOF_LOAD_SECTORS equ 13
 
 ; IN bx: begin of memory area to dump
 ; IN ax: number of words to dump
-- 
cgit v1.2.3-54-g00ecf