Change kernel blob format to be option rom compatible

kernel/main.asm

@@ -1,36 +1,119 @@
-; assumptions about the starting envionment
-cpu 8086
-org 0x0000
-
-_startup:
-  mov ax, cs
-  mov ss, ax
-  mov sp, 0x0000
-  ; <0x0010 is BIOS segment when relocated to HMA
-  ; so we need a nop sled
-  times (0x10 - ($-$$)) nop
-main:
-  call intr_init
-
-  int 3
-
-  mov ah, 0x01
-  int 0x21
-  mov dl, al
-  mov ah, 0x02
-  int 0x21
-
-  sti
-.halt:
-  hlt
-  jmp .halt
-
-%include "intr.asm"
-%include "debug.asm"
-%include "kprintf.asm"
-%include "dosapi.asm"
-
-_reloc_end:
-
-align 16
-heap:
+cpu 8086
+org 0x0000
+  db 0x55, 0xAA, 0x00
+  jmp optrom_init
+
+times (0x1A - ($-$$)) db 0
+  dw pnp
+
+align 16
+pnp:
+  db "$PnP"
+  db 1 ; version 1
+  db 2 ; 2 * 16 length
+  dw 0 ; offset of next header
+  db 0
+  db 0 ; checksum (filled by fix-rom)
+  dd 0 ; device identifier
+  dw .vendor ; manufacturer string
+  dw .product ; product name string
+  db 0,0,0 ; device type string
+  db 0x20 ; device indicator, bit for "read cacheable" set
+  dw 0 ; boot connection vector
+  dw 0 ; boot disconnect vector
+  dw start ; bootstrap entry point
+  dw 0 ; reserved
+  dw 0
+.vendor:
+  db "Nero", 0
+.product:
+  db "2B", 0
+
+align 16
+optrom_init:
+  push di
+  push es
+  xor ax, ax
+  mov es, ax
+  mov di, 0x0060 ; vector (0x18 * 4 bytes)
+  mov ax, start
+  stosw
+  mov ax, cs
+  stosw
+  pop es
+  pop di
+  retf
+
+start:
+  call intr_init
+
+  sti
+
+  mov si, 0x0000
+  mov ds, si
+
+.loop:
+  push bx
+  mov dx, 0x0000
+  mov ah, 0x02
+  mov bx, 0x0000
+  int 0x10
+  pop bx
+
+  call dump
+
+  mov ah, 0x01
+  int 0x21
+
+  cmp al, 0x30
+  jne .notup
+  sub bx, 0x0100
+.notup:
+  cmp al, 0x31
+  jne .notdown
+  add bx, 0x0100
+.notdown:
+  jmp .loop
+
+.halt:
+  hlt
+  jmp .halt
+
+dump:
+  mov si, bx
+  mov cx, 0x10
+.nextline:
+  mov ax, si
+  call kprint16
+
+  mov al, 0x3A
+  call kputc
+  mov al, 0x20
+  call kputc
+
+  push cx
+  mov cx, 0x0020
+.bytes:
+  lodsb
+  call kprint8
+  loop .bytes
+  pop cx
+
+  mov al,0x20
+  call kputc
+  mov al,0x0A
+  call kputc
+  mov al,0x0D
+  call kputc
+
+  loop .nextline
+  ret
+
+%include "intr.asm"
+%include "debug.asm"
+%include "kprintf.asm"
+%include "dosapi.asm"
+
+_reloc_end:
+
+align 512