untested memory manager & malloc + boot loader multitrack fix

 - implemented coarse 1k block allocator
 - implemented byte-granular kmalloc
 - fixed boot loader to properly read multiple tracks. Have to  use
   the BPB params for floppies, not drive params from int 13h/ah=8

diff --git a/kern/Makefile b/kern/Makefile
index 187df0d..39b8090 100644 (file)
--- a/kern/Makefile
+++ b/kern/Makefile
@@ -46,7 +46,8 @@ run: $(img)
 
 .PHONY: debug
 debug: $(img)
-       qemu-system-i386 -fda $(img) -serial file:serial.log -s -S
+       qemu-system-i386 -fda $(img) -serial file:serial.log -s -S &
+       gdb
 
 .PHONY: disasm
 disasm: $(bin)

diff --git a/kern/src/boot.asm b/kern/src/boot.asm
index b8966d4..529eae6 100644 (file)
--- a/kern/src/boot.asm
+++ b/kern/src/boot.asm
@@ -29,6 +29,7 @@ cur_cyl               equ 0514h       ; 2 bytes - current cylinder
 %%end: popf
 %endmacro
 
+BPB_NUM_HEADS          equ 2
 ; 5.25" 360K floppy
 BPB_DISK_SECTORS       equ 720
 BPB_TRACK_SECTORS      equ 9
@@ -52,7 +53,7 @@ bios_param_block:
        db BPB_MEDIA_TYPE       ; 15h: media descriptor type (f0 = 3.5" HD floppy)
        dw 9            ; 16h: number of sectors per FAT
        dw BPB_TRACK_SECTORS    ; 18h: number of sectors per track
-       dw 2            ; 1ah: number of heads
+       dw BPB_NUM_HEADS        ; 1ah: number of heads
        dd 0            ; 1ch: number of hidden sectors
        dd 0            ; 20h: high bits of sector count
        db 0            ; 24h: drive number
@@ -80,11 +81,14 @@ start:
 .setcs:
        mov sp, _bootsect_start ; temp stack below our relocated address
 
+       test dl, 80h    ; if high bit is set, it's a hard disk
+       jz .usebpb
+
        ; query sectors per track
        mov ah, 8       ; get drive parameters call, dl already has the drive
        xor di, di
        int 13h
-       jc .queryfail
+       jc .usebpb
        and cx, 3fh
        mov [sect_per_track], cx
        mov cl, 8
@@ -92,18 +96,17 @@ start:
        inc dx
        mov [num_heads], dx
        jmp .querydone
-.queryfail:
-       ; in case of failure, try 18 sectors per track, 2 heads
-       mov word [sect_per_track], 18
-       mov word [num_heads], 2
+.usebpb:
+       ; for hard disks and if the call fails, use the BPB values
+       mov word [sect_per_track], BPB_TRACK_SECTORS
+       mov word [num_heads], BPB_NUM_HEADS
 .querydone:
 
-       ; load the rest of the code high
+       ; load the rest of the code high [sect = (_kern_size + 511) / 512]
        mov ax, _kern_size
        add ax, 511
        mov cl, 9
        shr ax, cl
-       inc ax
        mov [sect_pending], ax
        mov ax, _kern_start_seg
        mov es, ax      ; destination segment
@@ -130,7 +133,7 @@ start:
        push dx
        push si
        call print_hex_word
-       mov ax, str_rdtrack2
+       mov ax, str_colon
        call printstr
        mov ax, [cur_cyl]
        call print_hex_byte
@@ -142,6 +145,14 @@ start:
        call printstr
        mov ax, [start_sect]
        call print_hex_byte
+       mov ax, str_rdtrack4
+       call printstr
+       mov ax, es
+       call print_hex_word
+       mov ax, str_colon
+       call printstr
+       mov ax, [destptr]
+       call print_hex_word
        mov ax, str_newline
        call printstr
        pop si
@@ -181,7 +192,6 @@ start:
 
        ; loaded sucessfully, load segment registers and jump
 .done: xor ax, ax
-       mov ds, ax
        mov es, ax
        push ax
        mov ax, _kern_start
@@ -253,9 +263,10 @@ print_hex_digit:
 .hexdig_tab:
        db "0123456789abcdef"
 
-str_rdtrack2   db " from ",0
 str_rdtrack3   db "/",0
-str_load_fail  db "Failed to load kernel!",0
+str_rdtrack4   db "->",0
+str_colon      db ":",0
+str_load_fail  db "Failed!"
 str_newline    db 13,10,0
 
        times 510-($-$$) db 0

diff --git a/kern/src/libc/malloc.c b/kern/src/libc/malloc.c
index 0f6d493..ac34038 100644 (file)
--- a/kern/src/libc/malloc.c
+++ b/kern/src/libc/malloc.c
@@ -1,6 +1,3 @@
-#ifndef MALLOC_H_
-#define MALLOC_H_
-
 #include "malloc.h"
 #include "mem.h"
 #include "asmutil.h"
@@ -21,6 +18,7 @@ struct memrange {
 static struct memrange __far *pool;
 static unsigned int freemem, num_alloc;
 
+
 int kmalloc_init(int numblk)
 {
        int first;
@@ -162,5 +160,3 @@ void kfree(void __far *p)
                }
        }
 }
-
-#endif /* MALLOC_H_ */