feat(boot/loader): preload kernel at 0xF000

.github/workflows/analyze.yml

@@ -19,7 +19,7 @@ jobs:
         
       - name: Run shellcheck
         run: |
-          shellcheck ./releasetools/cdimage.sh ./releasetools/floppyimage.sh ./releasetools/hdimages.sh  ./releasetools/image.defaults  ./releasetools/image.functions
+          shellcheck ./releasetools/cdimage.sh ./releasetools/floppyimage.sh ./releasetools/hdimage.sh  ./releasetools/image.defaults  ./releasetools/image.functions
 
       - name: Run CppCheck
         run: |

boot/efi/bootia32.asm

@@ -65,7 +65,6 @@ efimain:
 	call [fnOutputStr]
 	add esp, 8
 
-
 	; #=======================#
 	; search and load kernel
 	; openVolume()

boot/loader/disk.inc

@@ -1,7 +1,7 @@
 
 disk_read_sectors:
-	test byte [bDriveLBA], TRUE
+;	test byte [bDriveLBA], TRUE
-	je .lba_read
+;	je .lba_read
 	push ax
 	push bx
 	push cx
@@ -61,11 +61,11 @@ disk_packet:
 	dd 0
 
 
-sectors_per_track  dw 0
+sectors_per_track  dw 18
-heads_per_cylinder dw 0
+heads_per_cylinder dw 2
-bytes_per_sector   dw 0
+bytes_per_sector   dw 512
-sectors_per_FAT    dw 0
+sectors_per_FAT    dw 9
-FAT_count          db 0
+FAT_count          db 2
-reserved_sectors   dw 0
+reserved_sectors   dw 1
-root_dir_entries   dw 0
+root_dir_entries   dw 224
-sectors_per_cluster db 0
+sectors_per_cluster db 1

boot/loader/loader.asm

@@ -36,8 +36,6 @@ _start:
 	call a20_enable
 	jc .error_a20
 
-	xchg bx, bx
-
 	; check drive type
 	; dl <= 0x7F == floppy
 	; dl >= 0x80 == hard drive
@@ -70,7 +68,27 @@ _start:
 	call fat_search_root
 	jc .error_not_found
 
+	mov [pKernelStartFat], ax
 
+	; load fat
+	xor ax, ax
+	mov al, [FAT_count]
+	mul word [sectors_per_FAT]
+	mov cx, ax
+	mov ax, [reserved_sectors]
+
+	xor bx, bx
+
+	call disk_read_sectors
+	
+	; load stage 2
+	mov ax, KERNEL_PRELOAD/0x10
+	mov es, ax
+	mov ax, [pKernelStartFat]
+	xor bx, bx
+	call fat_load_binary
+
+	xchg bx, bx
     ; fetch memory map from bios
 	call memory_get_map
 	jc .error_memory
@@ -122,11 +140,13 @@ _start:
 uDrive    rb 1
 bDriveLBA db FALSE
 
-szMsgStage2        db "StupidOS Loader %x", 0
+pKernelStartFat    dw 0
+
+szMsgStage2        db "StupidOS Loader", 0
 szKernelFile       db "VMSTUPIDSYS", 0
 szMsgErrorA20      db "ERROR: can't enable a20 line", 0
 szMsgErrorMemory   db "ERROR: can't detect available memory", 0
-szMsgErrorSector   db "ERROR: reading sector", CR, LF, 0 
+szMsgErrorSector   db "ERROR: reading sector", CR, LF, 0
 szMsgErrorNotFound db "ERROR: kernel not found", 0
 
 	use32

boot/loader/logger.inc

@@ -62,7 +62,6 @@ bios_log_hex:
 	mov si, szHexBuffer
 	xor cl, cl
 .loop:
-	xchg bx, bx
 	cmp cl, 8
 	je .print_number
 	rol edi, 4

boot/loader/memory.inc

@@ -66,8 +66,19 @@ memory_e820_get_map:
 	;;     CX - Configured 1
 	;;     DX - Configured 2
 memory_get_for_large_conf:
+	clc
 	mov ax, 0xE801
 	int 0x15
+	jc @f
+	xor ecx, ecx
+	mov cx, ax
+	push ecx
+	mov cx, bx
+	push ecx
+	mov si, szMsgLarge
+	call bios_log
+@@:
+	ret
 
 	;; Function: memory_get_extended_memory_size
 	;;
@@ -78,5 +89,30 @@ memory_get_for_large_conf:
 	;;    CF - Non-Carry - indicates no error
 	;;    AX - Number of contiguous KB above 1MB
 memory_get_map:
+	call memory_get_for_large_conf
+	jnc .end
 	clc
+	mov ah, 0x88
+	int 0x15
+
+	jc .end
+
+	xor ebx, ebx
+	mov bx, ax
+	push ebx
+	mov si, szMsgMaxMemKB
+	call bios_log
+
+	shr ebx, 2
+
+	push ebx
+	mov si, szMsgMaxPage
+	call bios_log
+
+.end:
 	ret
+
+
+szMsgMaxMemKB db "%x KB above 1MB", 0
+szMsgMaxPage db "%x pages", 0
+szMsgLarge db "%x KB above 1MB - %x * 64 KB above 16MB", 0