# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1297835425 -7200
# Node ID 78d5c304ddd075368204e1eb1328cf466548d976
# Parent  611b2d66420bd94f9f0c7c45101dfd1e18200501
minor changes

diff -r 611b2d66420b -r 78d5c304ddd0 src/segm-asm.S
--- a/src/segm-asm.S	Wed Feb 16 07:26:03 2011 +0200
+++ b/src/segm-asm.S	Wed Feb 16 07:50:25 2011 +0200
@@ -1,27 +1,25 @@
 	.data
+	.align 4
+/* memory reserved for setup_selectors */
 off:.long 0
 seg:.short 0
-
-	.align
-	.short 0
-gdt_lim:
-	.short 0
-gdt_addr:
-	.long 0
+/* memory reserved for set_gdt */
+lim:.short 0
+addr:.long 0
 
 	.text
 /* setup_selectors(uint16_t code, uint16_t data)
  * loads the requested selectors to all the selector registers */
 	.globl setup_selectors
 setup_selectors:
-	/* setup data selectors */
+	/* set data selectors directly */
 	movl 8(%esp), %eax
 	movw %ax, %ss
 	movw %ax, %es
 	movw %ax, %ds
 	movw %ax, %gs
 	movw %ax, %fs
-	/* setup code selector */
+	/* set cs using a long jump */
 	movl 4(%esp), %eax
 	movw %ax, (seg)
 	movl $ldcs, (off)
@@ -34,8 +32,8 @@
 	.globl set_gdt
 set_gdt:
 	movl 4(%esp), %eax
-	movl %eax, (gdt_addr)
+	movl %eax, (addr)
 	movw 8(%esp), %ax
-	movw %ax, (gdt_lim)
-	lgdt (gdt_lim)	
+	movw %ax, (lim)
+	lgdt (lim)	
 	ret
diff -r 611b2d66420b -r 78d5c304ddd0 src/segm.c
--- a/src/segm.c	Wed Feb 16 07:26:03 2011 +0200
+++ b/src/segm.c	Wed Feb 16 07:50:25 2011 +0200
@@ -1,6 +1,7 @@
 #include <string.h>
 #include "segm.h"
 
+/* bits for the 3rd 16bt part of the descriptor */
 #define BIT_ACCESSED	(1 << 8)
 #define BIT_WR			(1 << 9)
 #define BIT_RD			(1 << 9)
@@ -10,6 +11,7 @@
 #define BIT_NOSYS		(1 << 12)
 #define BIT_PRESENT		(1 << 15)
 
+/* bits for the last 16bit part of the descriptor */
 #define BIT_BIG			(1 << 6)
 #define BIT_DEFAULT		(1 << 6)
 #define BIT_GRAN		(1 << 7)
@@ -18,7 +20,12 @@
 
 static void segm_desc(desc_t *desc, uint32_t base, uint32_t limit, int dpl, int type);
 
+/* these functions are implemented in segm-asm.S */
+void setup_selectors(uint16_t code, uint16_t data);
+void set_gdt(uint32_t addr, uint16_t limit);
 
+
+/* our global descriptor table */
 static desc_t gdt[4];
 
 
@@ -33,6 +40,7 @@
 	setup_selectors(selector(SEGM_KCODE, 0), selector(SEGM_KDATA, 0));
 }
 
+/* constructs a GDT selector based on index and priviledge level */
 uint16_t selector(int idx, int rpl)
 {
 	return (idx << 3) | (rpl & 3);
diff -r 611b2d66420b -r 78d5c304ddd0 src/segm.h
--- a/src/segm.h	Wed Feb 16 07:26:03 2011 +0200
+++ b/src/segm.h	Wed Feb 16 07:50:25 2011 +0200
@@ -12,10 +12,5 @@
 
 uint16_t selector(int idx, int rpl);
 
-/* these functions are implemented in segm-asm.S */
-void setup_selectors(uint16_t code, uint16_t data);
-void set_gdt(uint32_t addr, uint16_t limit);
-
-
 
 #endif	/* SEGM_H_ */