intr: Ship table with first 16 ISR offsets

kernel/debug.asm

@@ -1,13 +1,3 @@
-debug_init:
-  push bx
-  push dx
-  mov bx, 0x002E
-  mov dx, debug_reg_ir
-  call ivt_set
-  pop dx
-  pop bx
-  ret
-
 ; this kprints registers
 ; expect to be called as interrupt routine
 debug_reg_ir:

kernel/intr.asm

@@ -1,33 +1,102 @@
-ivt_backup:
+; Data table for interrupts
+; cs:word for service routine
+intr_table:
+  dw iret ;  0 Divide by Zero
+  dw iret ;  1 Single Step
+  dw iret ;  2 Parity error routine (NMI)
+  dw debug_reg_ir ;  3 Break
+  dw iret ;  4 Overflow
+  dw iret ;  5 Print Screen
+  dw iret ;  6 Mouse button control
+  dw iret ;  7 Reserved
+  dw irq0 ;  8 System Clock interrupt
+  dw irq1 ;  9 Keyboard interrupt
+  dw irq2 ; 10 RTC interrupt
+  dw irq3 ; 11 COMMS
+  dw irq4 ; 12 COMMS
+  dw irq5 ; 13 Hard Disk
+  dw irq6 ; 14 Floppy Disk interrupt routine
+  dw irq7 ; 15 Printer interrupt
+
+; LSB is IRQ0, MSB is IRQ16
+; A IRQ will set their bit to 1, so userspace may poll it via wait_irq
+intr_flip:
+  dw 0
+
+intr_init:
   push ds
   push es
+  ; backup intr 0x0n to 0x4n
   xor ax, ax
-  mov ds, ax
+  mov ds, ax ; read from IVT
-  mov es, ax
+  mov es, ax ; write to IVT
-  mov si, ax
+  mov si, ax ; read from start of IVT table
-  mov di, 0x0100 ; int 0x40 address
+  mov di, 0x0100 ; write to offset of int 0x40 address
-  mov cx, 0x0040 ; 0x20 interrupts * 2 words
+  mov cx, 0x0020 ; 0x10 interrupts, segment:offset each
   repe movsw
+  ; now setup our own handlers
+  mov ax, cs
+  mov ds, ax ; read from local segment
+  mov si, intr_table ; read from intr_table
+  mov di, 0x0000 ; write to start of IVT table
+  mov cx, 0x0010 ; 0x10 interupts, one offset each
+.loop:
+  movsw ; read offset, write offset
+  mov ax,cs
+  stosw ; write segment
+  loop .loop
   pop es
   pop ds
   ret
 
-; set item in interrupt vector table
+irq0:
-; in:	bx	interrupt number
+  int 0x48
-;	cs:dx	new handler address
+  or byte [intr_flip], 0x01
-ivt_set:
+  jmp irqret
+
+irq1:
+  int 0x49
+  or byte [intr_flip], 0x02
   push ax
-  push es
+  mov ax, [intr_flip]
-
+  call kprint8
-  xor ax,ax
+  mov word [intr_flip], 0x0000
-  mov es,ax
-
-  sal bx,1
-  sal bx,1
-
-  mov [es:bx], dx
-  mov [es:bx+2], cs
-
-  pop es
   pop ax
-  ret
+  jmp irqret
+
+irq2:
+  int 0x4A
+  or byte [intr_flip], 0x04
+  jmp irqret
+
+irq3:
+  int 0x4B
+  or byte [intr_flip], 0x08
+  jmp irqret
+
+irq4:
+  int 0x4C
+  or byte [intr_flip], 0x10
+  jmp irqret
+
+irq5:
+  int 0x4D
+  or byte [intr_flip], 0x20
+  jmp irqret
+
+irq6:
+  int 0x4E
+  or byte [intr_flip], 0x40
+  jmp irqret
+
+irq7:
+  int 0x4F
+  or byte [intr_flip], 0x80
+  jmp irqret
+
+hwiret:
+  mov al,20h
+  out 20h,al
+irqret:
+iret:
+  iret

kernel/main.asm

@@ -10,21 +10,15 @@ _startup:
   ; so we need a nop sled
   times (0x10 - ($-$$)) nop
 main:
-  call hma_relocate
+  call intr_init
-  call ivt_backup
-  call debug_init
 
-  int 0x2E
+  int 3
-  mov ax,0x1234
-  int 0x2E
-  call kprint16
 
+  sti
 .halt:
   hlt
   jmp .halt
 
-%include "hma.asm"
-
 %include "heap.asm"
 %include "intr.asm"
 %include "debug.asm"