0.556s-int: init IDT and set handler

LINES

@@ -16,3 +16,5 @@
 
 2021-2-23 0.509: 509 lines, 6 files, rain
 
+2021-2-23 0.556: 556 lines, 6 files, rain
+

README.md

@@ -45,6 +45,9 @@ Cunix kernel
 `0.509s-kernel`: 
 &#9load kernel to 0x8200-0x9200 for 4KB, kernel.asm display 'K' to screen. 
 
+`0.556s-int`: 
+&#9init IDT at 0x0000-0x1000, and set all handler at ignore_int, but it do nothing. 
+
 </pre>
 
 

kernel/kernel.asm

@@ -17,10 +17,57 @@
 
 
 
+org 0x8200
+
 bits 64
 
 _start:
 	mov byte [0xb8000], 'K'
-	hlt
+
+	call setup_idt
+	lidt [idt64_descriptor]
+
+	sti
+
 	jmp $
 
+
+setup_idt:
+	lea rdx, ignore_int
+	mov rax, (0x08 << 16)
+	mov ax, dx
+	mov rcx, (0x8e00 << 32)
+	add rax, rcx
+	mov ecx, edx
+	shr ecx, 16
+	shl rcx, 48
+	add rax, rcx
+	shr rdx, 32
+
+	; we save IDT at 0x0000000000000000 like BIOS
+	lea rdi, 0x0000000000000000
+	mov rcx, 256
+
+.setup_loop:
+	mov [rdi], rax
+	mov [rdi + 8], rdx
+	add rdi, 0x10
+	dec rcx
+	jne .setup_loop
+
+	ret
+
+
+ignore_int:
+	add byte [0xb8000], 1
+
+	; CPU will cli when it call ignore_int
+	hlt
+
+
+idt64_length equ 0xff * 16
+
+idt64_descriptor:
+	dw idt64_length
+	dd 0x0000000000000000
+