optimized MBR and added memmap identification

3 files changed, 154 insertions, 94 deletions

diff --git a/boot/common.asm b/boot/common.asm
index c241f55..323b54f 100644
--- a/boot/common.asm
+++ b/boot/common.asm
@@ -12,89 +12,90 @@
 
 [bits 16]
 
-
-;global data
-STR_HEX_OUT:
-    db "0x0000",0
-
-;print_string routine ([bx])
-;this routine will print a null terminated string at [bx] to the screen.
-print_string:
-
-    pusha			;push all registers
-    mov ah,0x0e
-
-    print_string_loop:
-
-	;check if value at [bx] is "\0" (end of string)
-	mov cl,[bx]
-	cmp cl,0
-	je print_string_finish
-
-	;otherwise instruct BIOS to print the current char
-	mov al,cl
-	int 0x10
-
-	;proceed with next char
-        inc bx
-	jmp print_string_loop
-
-    print_string_finish:
-
-    popa			;pop all registers
-    ret				;return to caller
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-;print_hex routine (dx)
-;will print the value of the bx register as hex to the screen
-print_hex:
-
-    pusha
-
-    ;begin with last hex val (hex_out[5])
-    mov bx,STR_HEX_OUT+5
-
-    ;lets loop throuth all 4 'digits'
-    print_hex_loop:
-
-    ;get least significan hex digit to cx
-    mov cx,dx
-    and cx,0x000F
-
-    ;check range (0-9 vs a-f)
-    cmp cx,10
-    jl print_hex_setnum
-
-    ;set hex a-f
-    mov al,'A'-10		
-    add al,cl
-    jmp print_hex_al
-
-    ;set hex 0-9
-    print_hex_setnum:
-    mov al,'0'		
-    add al,cl
-
-    ; set hex_out[bx] to al
-    print_hex_al:
-    mov [bx],al
-
-    ;proceed with the next significant hex 'digit'
-    dec bx
-    shr dx,4
-
-    ;check if finished (otherwise loop)
-    cmp bx,STR_HEX_OUT+1
-    jne print_hex_loop
-
-    ;output complete hex string and return to caller
-    mov bx,STR_HEX_OUT
-    call print_string
-    popa
-    ret
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;/*
+;;global data
+;STR_HEX_OUT:
+;    db "0x0000",0
+;
+;;print_string routine ([bx])
+;;this routine will print a null terminated string at [bx] to the screen.
+;print_string:
+;
+;    pusha			;push all registers
+;    mov ah,0x0e
+;
+;    print_string_loop:
+;
+;	;check if value at [bx] is "\0" (end of string)
+;	mov cl,[bx]
+;	cmp cl,0
+;	je print_string_finish
+;
+;	;otherwise instruct BIOS to print the current char
+;	mov al,cl
+;	int 0x10
+;
+;	;proceed with next char
+;        inc bx
+;	jmp print_string_loop
+;
+;    print_string_finish:
+;
+;    popa			;pop all registers
+;    ret				;return to caller
+;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;
+;;print_hex routine (dx)
+;;will print the value of the bx register as hex to the screen
+;print_hex:
+;
+;    pusha
+;
+;    ;begin with last hex val (hex_out[5])
+;    mov bx,STR_HEX_OUT+5
+;
+;    ;lets loop throuth all 4 'digits'
+;    print_hex_loop:
+;
+;    ;get least significan hex digit to cx
+;    mov cx,dx
+;    and cx,0x000F
+;
+;    ;check range (0-9 vs a-f)
+;    cmp cx,10
+;    jl print_hex_setnum
+;
+;    ;set hex a-f
+;    mov al,'A'-10		
+;    add al,cl
+;    jmp print_hex_al
+;
+;    ;set hex 0-9
+;    print_hex_setnum:
+;    mov al,'0'		
+;    add al,cl
+;
+;    ; set hex_out[bx] to al
+;    print_hex_al:
+;    mov [bx],al
+;
+;    ;proceed with the next significant hex 'digit'
+;    dec bx
+;    shr dx,4
+;
+;    ;check if finished (otherwise loop)
+;    cmp bx,STR_HEX_OUT+1
+;    jne print_hex_loop
+;
+;    ;output complete hex string and return to caller
+;    mov bx,STR_HEX_OUT
+;    call print_string
+;    popa
+;    ret
+;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;*/
 
 ;disk_load routune (load dh sectors from drive dl to es:bx)
 disk_load:
diff --git a/boot/mbr.asm b/boot/mbr.asm
index a6dc876..12b7707 100644
--- a/boot/mbr.asm
+++ b/boot/mbr.asm
@@ -27,11 +27,12 @@ jmp boot_16 ;start boot process
 
 ;SOME Global Data, mainly strings
 STR_VERSION:
-    db "_<-Fool-Loader~0.0.13~",0
+;    db "v0.2~",0
 STR_PROT:
-    db "Entered 32-bit Protected Mode.",0
+;    db "32-bit PM",0
 STR_LOADED:
-    db "FoolOS Kernel Loaded.",0
+;    db "loaded",0
+
 BOOT_DRIVE:
     db 0
 
@@ -42,7 +43,7 @@ BOOT_DRIVE:
 %include "boot/common.asm"
 
 ;include 32-bit Protected Mode routines (print_string_pm,print_hex_pm)
-%include "boot/common_pm.asm"
+;%include "boot/common_pm.asm"
 
 ;include our routines for switching to 32-bit protected mode
 %include "boot/pm.asm"
@@ -50,6 +51,9 @@ BOOT_DRIVE:
 ;pic mapping
 %include "boot/pic.asm"
 
+;memory map
+%include "boot/memmap.asm"
+
 ;;;;;;;; BOOT 16-bit real ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 ;lets start
@@ -64,8 +68,8 @@ boot_16:
     mov [BOOT_DRIVE],dl	
 
     ;print FoolOS version info
-    mov bx, STR_VERSION
-    call print_string
+;    mov bx, STR_VERSION
+;    call print_string
 
     ;Load the KERNEL
     mov bx,KERNEL_OFFSET
@@ -74,8 +78,8 @@ boot_16:
     call disk_load
 
     ;print info message that kernel was loaded
-    mov bx, STR_LOADED
-    call print_string
+;    mov bx, STR_LOADED
+;    call print_string
 
     ;finally lets enter Protected mode!!!
     call switch_to_pm
@@ -85,9 +89,9 @@ boot_16:
 boot_32_pm:
 
     ;print info message that we are in protected mode!
-    mov ecx,160
-    mov ebx,STR_PROT
-    call print_string_pm
+;    mov ecx,160
+;    mov ebx,STR_PROT
+;    call print_string_pm
 
     ;enable A20
     ;http://www.brokenthorn.com/Resources/OSDev9.html
diff --git a/boot/memmap.asm b/boot/memmap.asm
new file mode 100644
index 0000000..29d48f3
--- /dev/null
+++ b/boot/memmap.asm
@@ -0,0 +1,55 @@
+;---------------------------------------------
+;	Get memory map from bios
+;	/in es:di->destination buffer for entries
+;	/ret bp=entry count
+;---------------------------------------------
+
+; stolen from: http://www.brokenthorn.com/Resources/OSDev17.html
+struc	MemoryMapEntry
+    .baseAddress	resq	1	; base address of address range
+    .length		resq	1	; length of address range in bytes
+    .type		resd	1	; type of address range
+    .acpi_null	resd	1	; reserved
+endstruc
+ 
+[bits 16]
+
+BiosGetMemoryMap:
+    pushad
+    xor	ebx, ebx
+    xor	bp, bp			; number of entries stored here
+    mov	edx, 'PAMS'		; 'SMAP'
+    mov	eax, 0xe820
+    mov	ecx, 24			; memory map entry struct is 24 bytes
+    int	0x15			; get first entry
+    jc	.error	
+    cmp	eax, 'PAMS'		; bios returns SMAP in eax
+    jne	.error
+    test	ebx, ebx		; if ebx=0 then list is one entry long; bail out
+    je	.error
+    jmp	.start
+.next_entry:
+    mov	edx, 'PAMS'		; some bios's trash this register
+    mov	ecx, 24			; entry is 24 bytes
+    mov	eax, 0xe820
+    int	0x15			; get next entry
+.start:
+    jcxz	.skip_entry		; if actual returned bytes is 0, skip entry
+.notext:
+    mov	ecx, [es:di + MemoryMapEntry.length]	; get length (low dword)
+    test	ecx, ecx		; if length is 0 skip it
+    jne	short .good_entry
+    mov	ecx, [es:di + MemoryMapEntry.length + 4]; get length (upper dword)
+    jecxz	.skip_entry		; if length is 0 skip it
+.good_entry:
+    inc	bp			; increment entry count
+    add	di, 24			; point di to next entry in buffer
+.skip_entry:
+    cmp	ebx, 0			; if ebx return is 0, list is done
+    jne	.next_entry		; get next entry
+    jmp	.done
+.error:
+    stc
+.done:
+    popad
+    ret