内存容量检查（2）

yourtion · Apr 12, 2016 · 49287c1 · 49287c1
1 parent 1b0cded
commit 49287c1
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Showing 2 changed files with 34 additions and 26 deletions.
diff --git a/09_day/bootpack.c b/09_day/bootpack.c
@@ -4,7 +4,6 @@
 #include <stdio.h>
 
 unsigned int memtest(unsigned int start, unsigned int end);
-unsigned int memtest_sub(unsigned int start, unsigned int end);
 
 void HariMain(void)
 {
@@ -129,28 +128,3 @@ unsigned int memtest(unsigned int start, unsigned int end)
 
 	return i;
 }
-
-unsigned int memtest_sub(unsigned int start, unsigned int end)
-{
-	unsigned int i, *p, old, pat0 = 0xaa55aa55, pat1 = 0x55aa55aa;
-	for (i = start; i <= end; i += 0x1000) {
-		p = (unsigned int *) (i + 0xffc);
-		old = *p; /* 先记住修改前的值 */
-		*p = pat0; /* 试写 */
-		*p ^= 0xffffffff; /* 反转 */
-		if (*p != pat1) { 
-			/* 检查反转结果 */
-			not_memory:
-			*p = old;
-			break;
-		}
-		*p ^= 0xffffffff; /* 再次反转 */
-		if (*p != pat0) { 
-			/* 检查值是否恢复 */
-			 goto not_memory;
-		}
-		*p = old; /* 恢复为修改前的值 */
-	}
-	return i;
-}
-
diff --git a/09_day/naskfunc.nas b/09_day/naskfunc.nas
@@ -13,6 +13,7 @@
 		GLOBAL	_load_gdtr, _load_idtr
 		GLOBAL	_load_cr0, _store_cr0
 		GLOBAL	_asm_inthandler21, _asm_inthandler27, _asm_inthandler2c
+		GLOBAL	_memtest_sub
 		EXTERN	_inthandler21, _inthandler27, _inthandler2c
 
 [SECTION .text]
@@ -148,3 +149,36 @@ _asm_inthandler2c:
 		POP		DS
 		POP		ES
 		IRETD
+
+_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
+		PUSH	EBX
+		MOV		ESI,0xaa55aa55			; pat0 = 0xaa55aa55;
+		MOV		EDI,0x55aa55aa			; pat1 = 0x55aa55aa;
+		MOV		EAX,[ESP+12+4]			; i = start;
+mts_loop:
+		MOV		EBX,EAX
+		ADD		EBX,0xffc				; p = i + 0xffc;
+		MOV		EDX,[EBX]				; old = *p;
+		MOV		[EBX],ESI				; *p = pat0;
+		XOR		DWORD [EBX],0xffffffff	; *p ^= 0xffffffff;
+		CMP		EDI,[EBX]				; if (*p != pat1) goto fin;
+		JNE		mts_fin
+		XOR		DWORD [EBX],0xffffffff	; *p ^= 0xffffffff;
+		CMP		ESI,[EBX]				; if (*p != pat0) goto fin;
+		JNE		mts_fin
+		MOV		[EBX],EDX				; *p = old;
+		ADD		EAX,0x1000				; i += 0x1000;
+		CMP		EAX,[ESP+12+8]			; if (i <= end) goto mts_loop;
+		JBE		mts_loop
+		POP		EBX
+		POP		ESI
+		POP		EDI
+		RET
+mts_fin:
+		MOV		[EBX],EDX				; *p = old;
+		POP		EBX
+		POP		ESI
+		POP		EDI
+		RET