Implement ramdisk i/o, advance kernel printf

kernel/main.asm

@@ -1,8 +1,17 @@
 cpu 8086
 org 0x0000
-  db 0x55, 0xAA, 0x00
+  db 0x55, 0xAA
+optrom_length:
+  db 0x00
   jmp optrom_init
 
+str_vendor:
+  db "Nero", 0
+
+align 16
+str_product:
+  db "Nero DOS", 0
+
 times (0x1A - ($-$$)) db 0
   dw pnp
 
@@ -15,8 +24,8 @@ pnp:
   db 0
   db 0 ; checksum (filled by fix-rom)
   dd 0 ; device identifier
-  dw .vendor ; manufacturer string
-  dw .product ; product name string
+  dw str_vendor ; manufacturer string
+  dw str_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
@@ -24,15 +33,9 @@ pnp:
   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)
@@ -40,74 +43,71 @@ optrom_init:
   stosw
   mov ax, cs
   stosw
-  pop es
-  pop di
   retf
 
-start:
-  call intr_init
-
-  sti
-
-  mov si, 0x0000
-  mov ds, si
-
-.loop:
+putc:
   push bx
-  mov dx, 0x0000
-  mov ah, 0x02
+  push cx
+  mov ah, 0x0e
   mov bx, 0x0000
   int 0x10
+  pop cx
   pop bx
+  ret
 
-  call dump
+announce:
+  push cs
+  mov ax, str_product
+  push ax
+  call printf
+  db "%S (CS=%Xh)", 0x0A, 0x0D, 0x00
+  add sp, 4
+  ret
 
-  mov ah, 0x01
-  int 0x21
+start:
+  mov ax, cs
+  mov ds, ax
 
-  cmp al, 0x30
-  jne .notup
-  sub bx, 0x0100
-.notup:
-  cmp al, 0x31
-  jne .notdown
-  add bx, 0x0100
-.notdown:
-  jmp .loop
+  call announce
+
+  ; clear memory until 0x01000
+  xor ax, ax
+  mov es, ax
+  mov di, 0x500
+  mov cx, 0xB00
+  rep stosb
+
+  call intr_init
+  sti
+
+  sub sp, 0x10
+  mov si, sp
+  mov word [ss:si+0x00], 0
+  mov word [ss:si+0x02], 1
+  mov word [ss:si+0x04], 0
+  mov word [ss:si+0x06], 0x2000
+  mov word [ss:si+0x08], 0x07fc
+  mov word [ss:si+0x0A], 0
+  mov word [ss:si+0x0C], 0
+  mov word [ss:si+0x0E], 0
+  mov ah, 0x42
+
+  push ss
+  pop ds
+  call ramdisk_io
+  push ax
+  call printf
+  db "AX=%X", 0x0A, 0x0D, 0x00
+  pop ax
+
+  add sp, 0x10
 
 .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 "ramdisk.inc"
+%include "printf.inc"
 
 %include "intr.asm"
 %include "debug.asm"