cleanup boot directory

1 files changed, 35 insertions, 58 deletions

diff --git a/boot/mbr.asm b/boot/mbr.asm
index 32f1a6f..2beac7b 100644
--- a/boot/mbr.asm
+++ b/boot/mbr.asm
@@ -6,12 +6,31 @@
 ;    
 ;    we have just been loaded by the BIOS and are in 16-bits real mode!
 ;
-;   THIS IS THE CENTRAL FILE OF THE BOOTLOADER, after we finished we
-;   are inside the C kernel!
+;   THIS IS THE CENTRAL FILE OF THE BOOTLOADER, 
+;
+;   after we are through,
+;   the following work has been accomplished (chronologically):
+;
+;	* BOOT_DRIVE is set 
+;
+;	* 50 sectors of our kernel are loaded at KERNEL_OFFSET from floppy
+;
+;	* memoru map is available at MEMMAP_OFFSET 
+;	    (look at MEMMEP_SIZE_OFFSET for number of entries)
+;
+;	* the vesa mode specified by VESA_MODE_SELECT is set up 
+;	    (at VESA_MODES, and VESA_MODE_INFO additional info structs are available)
+;
+;	* 32-bit protected mode was set up.
+;
+;	* A20 gate is open
+;
+;	* PICs are configured
+;
+;	* we are inside the C kernel!
 ;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-;we want 16-bit instructions, before we switch to 32-bit protected mode.
 
 ;define origin of boot record in memory: 0x7c00
 ;this is where the BIOS per definition will put the first 
@@ -19,42 +38,34 @@
 ;The Boot record is identified by the last 2 magic bytes: 0xaa55 (?)
 [org 0x7c00]
 
-;define where we will load our kernel into memory
+;define where we will load our kernel into memory and some 
+;other memory locations
 KERNEL_OFFSET equ 0x1000
 MEMMAP_SIZE_OFFSET equ 0x7c00+0x600
 MEMMAP_OFFSET equ 0x7c00+0x400
 VESA_MODES equ 0x8300
 VESA_MODE_INFO equ 0x8400
 VESA_MODE_SELECT equ 0x4114
-;VESA_MODE_SELECT equ 0x411A
 
+;we want 16-bit instructions, before we switch to 32-bit protected mode.
 [bits 16]
 jmp boot_16 ;start boot process
 
+;SOME Global Data, mainly strings
 BOOT_DRIVE:
     db 0xff
-
-;SOME Global Data, mainly strings
 STR_VERSION:
     db "v0.2~",0
 
 VESA_CHECK:
     db "vesa check.",0
 
-;STR_PROT:
-;    db "32-bit PM",0
-;STR_LOADED:
-;    db "loaded",0
-
 ;lets put our temporary GDT (Global Descriptor Table) here
 %include "boot/GDT.asm"
 
 ;include 16-bit real mode routines (print_string, disk_load)
-%include "boot/common.asm"
-%include "boot/print16.asm"
-
-;include 32-bit Protected Mode routines (print_string_pm,print_hex_pm)
-;%include "boot/common_pm.asm"
+%include "boot/disk_load_16.asm"
+%include "boot/print_string_16.asm"
 
 ;include our routines for switching to 32-bit protected mode
 %include "boot/pm.asm"
@@ -62,7 +73,7 @@ VESA_CHECK:
 ;pic mapping
 %include "boot/pic.asm"
 
-;memory map
+;get memory map
 %include "boot/memmap.asm"
 
 ;;;;;;;; BOOT 16-bit real ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -82,21 +93,12 @@ boot_16:
     ;remember BOOT_DRIVE (as was set by BIOS)
     mov [BOOT_DRIVE],dl	
 
-    ;print FoolOS version info
-;    mov bx, STR_VERSION
-;    call print_string
-
-    ;Load the KERNEL
+    ;Load the KERNEL (50 sectors starting at sector 2)
     mov bx,KERNEL_OFFSET
     mov dh, 50	;50 sectors!
     mov dl, [BOOT_DRIVE]
     call disk_load
 
-    ;print info message that kernel was loaded
-;    mov bx, STR_LOADED
-;    call print_string
-
-
     ;get memory map from bios before we enter 32 bit protected mode
     mov ax,0	; set target address in es:di (0:offset)
     mov es,ax
@@ -104,7 +106,8 @@ boot_16:
     call BiosGetMemoryMap    ; this will also put the number of entries 
 			    ; of the memory map at MEMMAP_SIZE_OFFSET
 
-    ;get vesa modes!
+    ;VESA:  also setup vesa stuff before entering 32 bit protected mode
+    ;VESA: get all available vesa modes!
     mov ax,0	; set target address in es:di (0:offset)
     mov es,ax
     mov di,VESA_MODES
@@ -119,7 +122,7 @@ boot_16:
     vesa_ok:
     ;
 
-    ;get info on mode of interest
+    ;VESA: get vesa info on mode of interest
     mov ax,0	; set target address in es:di (0:offset)
     mov es,ax
     mov di,VESA_MODE_INFO
@@ -134,7 +137,7 @@ boot_16:
     jmp vesa_err2
     vesa_ok2:
 
-    ;finally switch to the mode of choice!
+    ;VESA: finally switch to the mode of choice!
     mov ax,0x4f02   ;vesa function: Set Mode
     mov bx,VESA_MODE_SELECT 
     int 0x10
@@ -148,11 +151,6 @@ boot_32_pm:
 
 ;  we could do ALL This inside the kernel!!!!!! TODO
 
-    ;print info message that we are in protected mode!
-;    mov ecx,160
-;    mov ebx,STR_PROT
-;    call print_string_pm
-
     ;enable A20
     ;http://www.brokenthorn.com/Resources/OSDev9.html
     ;Method 3.1: Enables A20 through keyboard controller
@@ -162,32 +160,11 @@ boot_32_pm:
     ;pic setup
     call pic_setup
 
-    call KERNEL_OFFSET			        ;jump into our Kernel it
-
-;idt_descriptor:
-;    dw idt_end-idt_start-1
-;    dd KERNEL_OFFSET
-;;;; DEBUGGING STUFF
-;times 8 db '@'
-;dw interrupt
-;times 8 db '@'
-;dw interrupt2
-;times 8 db '@'
+    call KERNEL_OFFSET			        ;jump into our Kernel!
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-
 ;so we get identified as MBR
 times 510-($-$$) db 0
 dw 0xaa55
 
-;interrupt descriptor table (hardcoded address of interrupts:)
-;idt_start:
-;times 33 db 0x50,0x7c,0x08,0x00,0x00,10001110b,0x0,0x0
-;db 0x59,0x7c,0x08,0x00,0x00,10001110b,0x0,0x0
-;times 253 db 0x50,0x7c,0x08,0x00,0x00,10001110b,0x0,0x0
-;idt_end:
-
-
-
-