对异常的支持

21_day/bootpack.h

@@ -24,14 +24,16 @@ void load_idtr(int limit, int addr);
 int load_cr0(void);
 void store_cr0(int cr0);
 void load_tr(int tr);
+void asm_inthandler0d(void);
 void asm_inthandler20(void);
 void asm_inthandler21(void);
 void asm_inthandler27(void);
 void asm_inthandler2c(void);
 unsigned int memtest_sub(unsigned int start, unsigned int end);
 void farjmp(int eip, int cs);
-void start_app(int eip, int cs, int esp, int ds);
+void farcall(int eip, int cs);
 void asm_hrb_api(void);
+void start_app(int eip, int cs, int esp, int ds);
 
 /* fifo.c */
 struct FIFO32 {
@@ -246,6 +248,7 @@ void cmd_dir(struct CONSOLE *cons);
 void cmd_type(struct CONSOLE *cons, int *fat, char *cmdline);
 int cmd_app(struct CONSOLE *cons, int *fat, char *cmdline);
 void hrb_api(int edi, int esi, int ebp, int esp, int ebx, int edx, int ecx, int eax);
+int inthandler0d(int *esp);
 
 /* file.c */
 struct FILEINFO {

21_day/console.c

@@ -320,3 +320,10 @@ void hrb_api(int edi, int esi, int ebp, int esp, int ebx, int edx, int ecx, int
 	}
 	return;
 }
+
+int inthandler0d(int *esp)
+{
+	struct CONSOLE *cons = (struct CONSOLE *) *((int *) 0x0fec);
+	cons_putstr0(cons, "¥nINT 0D :¥n General Protected Exception.¥n");
+	return 1; /*强制结束程序*/
+}

21_day/dsctbl.c

@@ -23,6 +23,7 @@ void init_gdtidt(void)
 	load_idtr(LIMIT_IDT, ADR_IDT);
 
 	/* IDT设置*/
+	set_gatedesc(idt + 0x0d, (int) asm_inthandler0d, 2 * 8, AR_INTGATE32);
 	set_gatedesc(idt + 0x20, (int) asm_inthandler20, 2 * 8, AR_INTGATE32);
 	set_gatedesc(idt + 0x21, (int) asm_inthandler21, 2 * 8, AR_INTGATE32);
 	set_gatedesc(idt + 0x27, (int) asm_inthandler27, 2 * 8, AR_INTGATE32);

21_day/naskfunc.nas

@@ -15,11 +15,13 @@
 		GLOBAL	_load_tr
 		GLOBAL	_asm_inthandler20, _asm_inthandler21
 		GLOBAL	_asm_inthandler27, _asm_inthandler2c
+		GLOBAL	_asm_inthandler0d
 		GLOBAL	_memtest_sub
-		GLOBAL	_farjmp, _start_app
-		GLOBAL	_asm_hrb_api
+		GLOBAL	_farjmp, _farcall
+		GLOBAL	_asm_hrb_api, _start_app
 		EXTERN	_inthandler20, _inthandler21
 		EXTERN	_inthandler27, _inthandler2c
+		EXTERN	_inthandler0d
 		EXTERN	_hrb_api
 
 [SECTION .text]
@@ -273,6 +275,67 @@ _asm_inthandler2c:
 		POP		ES
 		IRETD
 
+_asm_inthandler0d:
+		STI
+		PUSH	ES
+		PUSH	DS
+		PUSHAD
+		MOV		AX,SS
+		CMP		AX,1*8
+		JNE		.from_app
+; 当操作系统活动时产生中断的情况和之前差不多
+		MOV		EAX,ESP
+		PUSH	SS				; 保存中断时的SS
+		PUSH	EAX				; 保存中断时的ESP
+		MOV		AX,SS
+		MOV		DS,AX
+		MOV		ES,AX
+		CALL	_inthandler0d
+		ADD		ESP,8
+		POPAD
+		POP		DS
+		POP		ES
+		ADD		ESP,4			; 在INT 0x0d中需要这句
+		IRETD
+.from_app:
+; 当应用程序活动时产生中断
+		CLI
+		MOV		EAX,1*8
+		MOV		DS,AX			; 先仅将DS设定为操作系统用
+		MOV		ECX,[0xfe4]		; 操作系统的ESP
+		ADD		ECX,-8
+		MOV		[ECX+4],SS		; 保存产生中断时的SS
+		MOV		[ECX  ],ESP		; 保存产生中断时的ESP
+		MOV		SS,AX
+		MOV		ES,AX
+		MOV		ESP,ECX
+		STI
+		CALL	_inthandler0d
+		CLI
+		CMP		EAX,0
+		JNE		.kill
+		POP		ECX
+		POP		EAX
+		MOV		SS,AX				; 将SS恢复为应用程序用
+		MOV		ESP,ECX			; 将ESP恢复为应用程序用
+		POPAD
+		POP		DS
+		POP		ES
+		ADD		ESP,4			; INT 0x0d需要这句
+		IRETD
+.kill:
+; 将应用程序强制结束
+		MOV		EAX,1*8			; 操作系统用的DS/SS
+		MOV		ES,AX
+		MOV		SS,AX
+		MOV		DS,AX
+		MOV		FS,AX
+		MOV		GS,AX
+		MOV		ESP,[0xfe4]		; 强制返回到start_app时的ESP
+		STI			; 切换完成后恢复中断请求
+		POPAD		; 恢复事先保存的寄存器值
+		RET
+
 _memtest_sub:	; unsigned int memtest_sub(unsigned int start, unsigned int end)
 		PUSH	EDI						; （由于还要使用EBX, ESI, EDI）
 		PUSH	ESI