不随操作系统版本而改变的API

20_day/dsctbl.c

@@ -27,6 +27,7 @@ void init_gdtidt(void)
 	set_gatedesc(idt + 0x21, (int) asm_inthandler21, 2 * 8, AR_INTGATE32);
 	set_gatedesc(idt + 0x27, (int) asm_inthandler27, 2 * 8, AR_INTGATE32);
 	set_gatedesc(idt + 0x2c, (int) asm_inthandler2c, 2 * 8, AR_INTGATE32);
+	set_gatedesc(idt + 0x40, (int) asm_cons_putchar, 2 * 8, AR_INTGATE32);
 
 	return;
 }

20_day/hlt.nas

@@ -1,12 +1,12 @@
 [BITS 32]
 		MOV		AL,'h'
-		CALL    2*8:0xbe8
+		INT  0x40
 		MOV		AL,'e'
-		CALL    2*8:0xbe8
+		INT  0x40
 		MOV		AL,'l'
-		CALL    2*8:0xbe8
+		INT  0x40
 		MOV		AL,'l'
-		CALL    2*8:0xbe8
+		INT  0x40
 		MOV		AL,'o'
-		CALL    2*8:0xbe8
+		INT  0x40
 		RETF

20_day/naskfunc.nas

@@ -218,10 +218,11 @@ _farcall:		; void farcall(int eip, int cs);
 		RET
 
 _asm_cons_putchar:
+		STI
 		PUSH		1
 		AND			EAX,0xff ; 将AH和EAX的高位置0，将EAX置为已存入字符编码的状态
 		PUSH    EAX
 		PUSH		DWORD [0x0fec] ; 读取内存并PUSH该值
 		CALL		_cons_putchar
 		ADD			ESP,12   ; 将栈中的数据丢弃
-		RETF
+		IRETD