From 67ee9510770674a4ef236168176bf85e0775ab7e Mon Sep 17 00:00:00 2001
From: Andreas Baumann <mail@andreasbaumann.cc>
Date: Thu, 18 May 2017 15:33:37 +0200
Subject: added port types which are check when calling port read/write
 functions

---
 src/Makefile             | 20 +++++++++++++-------
 src/README               |  3 ++-
 src/interrupts.asm       |  0
 src/interrupts.c         |  1 +
 src/interrupts.h         |  4 ++++
 src/kernel.c             |  1 -
 src/port.asm             | 35 ++++++++++++++++++++++++++++-------
 src/port.c               |  3 ++-
 src/port.h               | 18 +++++++++++++-----
 src/serial.c             |  8 ++++----
 src/serial.h             |  4 ++--
 src/stage1_functions.asm |  2 +-
 src/vga.c                | 24 ++++++++++++------------
 src/vga.h                |  6 +++---
 14 files changed, 85 insertions(+), 44 deletions(-)
 create mode 100644 src/interrupts.asm
 create mode 100644 src/interrupts.c
 create mode 100644 src/interrupts.h

diff --git a/src/Makefile b/src/Makefile
index f22b5c0..affe3e3 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1,7 +1,7 @@
 CC := gcc
 CFLAGS := -std=c99 -m32 -ffreestanding -O0 -g -Wall -Werror
 LD := ld
-LDFLAGS := -f elf32
+NASMFLAGS := -f elf32
 NASM := nasm
 OBJCOPY := objcopy
 
@@ -14,8 +14,8 @@ 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 12)
-	truncate -s 7168 image.tmp
+	# loads only the first sector, so adapt NOF_LOAD_SECTORS to 16)
+	truncate -s 8192 image.tmp
 	cat image.tmp magic.bin > image.bin
 	
 boot.bin: boot.asm gdt.asm stage1_functions.asm stage2_functions.asm switch_mode.asm
@@ -27,10 +27,10 @@ kernel.bin: kernel.elf
 kernel.sym: kernel.elf
 	$(OBJCOPY) --only-keep-debug kernel.elf kernel.sym
 
-kernel.elf: kernel.o console.o vga.o serial.o port.o port_asm.o string.o stdlib.o
+kernel.elf: kernel.o console.o vga.o serial.o port.o port_asm.o interrupts.o interrupts_asm.o string.o stdlib.o
 	$(LD) -o kernel.elf -N -n -Ttext 0x8400 --oformat elf32-i386 \
 		kernel.o console.o vga.o serial.o port.o port_asm.o \
-		string.o stdlib.o
+		interrupts.o interrupts_asm.o string.o stdlib.o
 
 magic.bin: magic.asm
 	$(NASM) magic.asm -f bin -o magic.bin
@@ -41,6 +41,9 @@ kernel.o: kernel.c
 port.o: port.c port.h
 	$(CC) $(CFLAGS) -c -o port.o port.c
 
+port_asm.o: port.asm
+	$(NASM) port.asm $(NASMFLAGS) -o port_asm.o
+
 console.o: console.c console.h vga.h serial.h
 	$(CC) $(CFLAGS) -c -o console.o console.c
 
@@ -50,8 +53,11 @@ vga.o: vga.c vga.h
 serial.o: serial.c serial.h
 	$(CC) $(CFLAGS) -c -o serial.o serial.c
 
-port_asm.o: port.asm
-	$(NASM) port.asm $(LDFLAGS) -o port_asm.o
+interrupts.o: interrupts.c interrupts.h
+	$(CC) $(CFLAGS) -c -o interrupts.o interrupts.c
+
+interrupts_asm.o: interrupts.asm
+	$(NASM) interrupts.asm $(NASMFLAGS) -o interrupts_asm.o
 
 string.o: string.c string.h
 	$(CC) $(CFLAGS) -c -o string.o string.c
diff --git a/src/README b/src/README
index bfd0795..ad6ca2a 100644
--- a/src/README
+++ b/src/README
@@ -1,7 +1,7 @@
 * boot.bin - boot sector (stage 1 and 2, total 2k), offset 0x7c00
   * boot.asm - the main boot sector code using:
 * kernel.bin - linked kernel with fix start offset 0x8400
-  * gdt.asm - the early GDT
+  * gdt.asm - the early GDT, flat memory model, no protection
   * stage1_functions.asm - real mode functions of the bootloader
   * stage2_functions.asm - protected mode primitive VGA routines
   * switch_mode.asm - early GTD loading and switching from real to protected mode
@@ -14,6 +14,7 @@ kernel utility routines
 * vga.c - VGA basic output routines for early kernel output
 * serial.c - serial output to COM1 (only sequential ASCII chars, no terminal)
 * port.c, port.asm - I/O ports
+* interrupts.c, interrups.asm - interrupt handlers
 
 C library routines
 * string.c
diff --git a/src/interrupts.asm b/src/interrupts.asm
new file mode 100644
index 0000000..e69de29
diff --git a/src/interrupts.c b/src/interrupts.c
new file mode 100644
index 0000000..e04d063
--- /dev/null
+++ b/src/interrupts.c
@@ -0,0 +1 @@
+#include "interrupts.h"
diff --git a/src/interrupts.h b/src/interrupts.h
new file mode 100644
index 0000000..53a1a60
--- /dev/null
+++ b/src/interrupts.h
@@ -0,0 +1,4 @@
+#ifndef INTERRUPTS_H
+#define INTERRUPTS_H
+
+#endif // INTERRUPTS_H
diff --git a/src/kernel.c b/src/kernel.c
index 69a3870..6408aa7 100644
--- a/src/kernel.c
+++ b/src/kernel.c
@@ -48,7 +48,6 @@ void entry( void )
 	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/port.asm b/src/port.asm
index 4f2b646..f1bc76b 100644
--- a/src/port.asm
+++ b/src/port.asm
@@ -1,25 +1,46 @@
 [bits 32]
 
-global port8_write
-global port8_read
+global port_write8
+global port_read8
 
-; void port8_write( port8_t *port, uint8_t data );
-port8_write:
+; typedef enum port_type_t {
+;	PORT_TYPE_8BIT = 0,
+;	PORT_TYPE_8BIT_SLOW = 1,
+;	PORT_TYPE_16BIT = 2,
+;	PORT_TYPE_32BIT = 3
+; } port_type_t;
+PORT_TYPE_8BIT equ 0
+PORT_TYPE_8BIT_SLOW equ 1
+PORT_TYPE_16BIT equ 2
+PORT_TYPE_32BIT equ 3
+
+; void port_write8( port_t *port, uint8_t data );
+port_write8:
 	push ebp
 	mov ebp, esp
 	mov ecx, [ebp+8]
 	mov edx, DWORD [ecx]
+	cmp edx, PORT_TYPE_8BIT
+	je .ok
+	int 10
+.ok:
+	mov edx, DWORD [ecx+4]
 	movzx ax, BYTE [ebp+12]
 	out dx, al
 	leave
 	ret
 
-; uint8_t port8_read( port8_t *port )
-port8_read:
+; uint8_t port_read8( port_t *port )
+port_read8:
 	push ebp
 	mov ebp, esp
 	mov ecx, DWORD [ebp+8]
-	mov edx, [ecx]
+	mov edx, DWORD [ecx]
+	cmp edx, PORT_TYPE_8BIT
+	je .ok
+	int 11
+.ok:
+	mov edx, [ecx+4]
 	in al, dx
 	leave
 	ret
diff --git a/src/port.c b/src/port.c
index f64cc69..8107936 100644
--- a/src/port.c
+++ b/src/port.c
@@ -1,6 +1,7 @@
 #include "port.h"
 
-void port8_init( port8_t *port, uint16_t number )
+void port_init( port_t *port, port_type_t type, uint16_t number )
 {
 	port->number = number;
+	port->type = type;
 }
diff --git a/src/port.h b/src/port.h
index a5e8bd8..28d07b7 100644
--- a/src/port.h
+++ b/src/port.h
@@ -3,12 +3,20 @@
 
 #include <stdint.h>
 
-typedef struct port8_t {
+typedef enum port_type_t {
+	PORT_TYPE_8BIT = 0,
+	PORT_TYPE_8BIT_SLOW = 1,
+	PORT_TYPE_16BIT = 2,
+	PORT_TYPE_32BIT = 3
+} port_type_t;
+
+typedef struct port_t {
+	port_type_t type;
 	uint16_t number; // port number, e.g. 0x3d4 VGA index register
-} port8_t;
+} port_t;
 
-void port8_init( port8_t *port, uint16_t number );
-void port8_write( port8_t *port, uint8_t data );
-uint8_t port8_read( port8_t *port );
+void port_init( port_t *port, port_type_t type, uint16_t number );
+void port_write8( port_t *port, uint8_t data );
+uint8_t port_read8( port_t *port );
 
 #endif //
diff --git a/src/serial.c b/src/serial.c
index 0ca3063..409b024 100644
--- a/src/serial.c
+++ b/src/serial.c
@@ -6,18 +6,18 @@ void serial_init( serial_t *serial )
 {
 	memset( serial, 0, sizeof( serial_t ) );
 
-	port8_init( &serial->port_3F8, 0x3F8 );
-	port8_init( &serial->port_3FD, 0x3FD );
+	port_init( &serial->port_3F8, PORT_TYPE_8BIT, 0x3F8 );
+	port_init( &serial->port_3FD, PORT_TYPE_8BIT, 0x3FD );
 }
 
 void serial_put_char( serial_t *serial, const char c )
 {
 	uint8_t status;
 	do {
-		status = port8_read( &serial->port_3FD );
+		status = port_read8( &serial->port_3FD );
 	} while( ( status & 0x20 ) == 0 );
 	
-	port8_write( &serial->port_3F8, c );
+	port_write8( &serial->port_3F8, c );
 }
 
 void serial_put_string( serial_t *serial, const char *s )
diff --git a/src/serial.h b/src/serial.h
index f50a62d..81c1e83 100644
--- a/src/serial.h
+++ b/src/serial.h
@@ -4,8 +4,8 @@
 #include "port.h"
 
 typedef struct serial_t {
-	port8_t port_3F8;
-	port8_t port_3FD;	
+	port_t port_3F8;
+	port_t port_3FD;	
 } serial_t;
 
 void serial_init( serial_t *serial );
diff --git a/src/stage1_functions.asm b/src/stage1_functions.asm
index 6a145f6..440b4be 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 14
+NOF_LOAD_SECTORS equ 16
 
 ; IN bx: begin of memory area to dump
 ; IN ax: number of words to dump
diff --git a/src/vga.c b/src/vga.c
index aba3564..609b831 100644
--- a/src/vga.c
+++ b/src/vga.c
@@ -21,12 +21,12 @@ void vga_init( vga_t *vga )
 
 	// 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 );
+	port_init( &vga->crtc_misc_port, PORT_TYPE_8BIT, 0x3d2 );
+	port_write8( &vga->crtc_misc_port, 1 );
 
 	// set up VGA ports
-	port8_init( &vga->crtc_index_port, 0x3d4 );
-	port8_init( &vga->crtc_data_port, 0x3d5 );
+	port_init( &vga->crtc_index_port, PORT_TYPE_8BIT, 0x3d4 );
+	port_init( &vga->crtc_data_port, PORT_TYPE_8BIT, 0x3d5 );
 	
 	vga_set_cursor_from_hardware( vga );	
 };
@@ -59,12 +59,12 @@ void vga_set_cursor_from_hardware( vga_t *vga )
 {
 	uint16_t hw_cursor_pos;
 	
-	port8_write( &vga->crtc_index_port, 14 );
-	uint8_t data = port8_read( &(vga->crtc_data_port ) );
+	port_write8( &vga->crtc_index_port, 14 );
+	uint8_t data = port_read8( &(vga->crtc_data_port ) );
 	hw_cursor_pos = data << 8;
  
-	port8_write( &vga->crtc_index_port, 15 );
-	data = port8_read( &(vga->crtc_data_port ) );
+	port_write8( &vga->crtc_index_port, 15 );
+	data = port_read8( &(vga->crtc_data_port ) );
 
 	hw_cursor_pos |= data;
 	
@@ -83,10 +83,10 @@ void vga_set_cursor_on_hardware( vga_t *vga )
 {
     uint16_t hw_cursor_pos = vga->cursor_x + vga->cursor_y * vga->res_x;
 
-    port8_write( &vga->crtc_index_port, 15 );
-    port8_write( &vga->crtc_data_port, hw_cursor_pos & 0xff );
-    port8_write( &vga->crtc_index_port, 14 );
-    port8_write( &vga->crtc_data_port, hw_cursor_pos >> 8 );
+    port_write8( &vga->crtc_index_port, 15 );
+    port_write8( &vga->crtc_data_port, hw_cursor_pos & 0xff );
+    port_write8( &vga->crtc_index_port, 14 );
+    port_write8( &vga->crtc_data_port, hw_cursor_pos >> 8 );
 }
 
 int vga_get_cursor_x( vga_t *vga )
diff --git a/src/vga.h b/src/vga.h
index 3a91154..bc2449a 100644
--- a/src/vga.h
+++ b/src/vga.h
@@ -34,9 +34,9 @@ typedef struct vga_t {
 	int cursor_y;	// current cursor position Y
 	vga_color_t color;
 	vga_color_t background_color;
-	port8_t crtc_misc_port;
-	port8_t crtc_index_port;
-	port8_t crtc_data_port;
+	port_t crtc_misc_port;
+	port_t crtc_index_port;
+	port_t crtc_data_port;
 } vga_t;
 
 void vga_init( vga_t *vga );
-- 
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