今天做项目的时候发现Keil中一个重大疑惑，也许是Keil的一个BUG.如下：
(STC89C52)
第一种情况：（正确的）
先进行位定义
sbit P10 = P1^0;
sbit P11 = P1^1;
sbit P12 = P1^2;
sbit P13 = P1^3;
然后在函数中使用
for(i=0;i<4;i++){
P1=~tmp;
if(P10==0){
keyTmp = (i*4+1);
goto out1;
}else if(P11==0){
keyTmp = (i*4+2);
goto out1;
}else if(P12==0){
keyTmp = (i*4+3);
goto out1;
}else if(P13==0){
keyTmp = (i*4+4);
goto out1;
}
tmp<<=1;
}
Keil的汇编结果如下：
50: for(i=0;i<4;i++){
C:0x005C E4 CLR A
C:0x005D FD MOV R5,A
51: P1=~tmp;
C:0x005E EF MOV A,R7
C:0x005F F4 CPL A
C:0x0060 F590 MOV P1(0x90),A
52: if(P10==0){
C:0x0062 209009 JB P10(0x90.0),C:006E
53: keyTmp = (i*4+1);
C:0x0065 ED MOV A,R5
C:0x0066 25E0 ADD A,ACC(0xE0)
C:0x0068 25E0 ADD A,ACC(0xE0)
C:0x006A 04 INC A
C:0x006B FE MOV R6,A
54: goto out1;
C:0x006C 804D SJMP C:00BB
55: }else if(P11==0){
C:0x006E 20910A JB P11(0x90.1),C:007B
56: keyTmp = (i*4+2);
C:0x0071 ED MOV A,R5
C:0x0072 25E0 ADD A,ACC(0xE0)
C:0x0074 25E0 ADD A,ACC(0xE0)
C:0x0076 2402 ADD A,#0x02
C:0x0078 FE MOV R6,A
57: goto out1;
C:0x0079 8040 SJMP C:00BB
58: }else if(P12==0){
C:0x007B 20920A JB P12(0x90.2),C:0088
59: keyTmp = (i*4+3);
C:0x007E ED MOV A,R5
C:0x007F 25E0 ADD A,ACC(0xE0)
C:0x0081 25E0 ADD A,ACC(0xE0)
C:0x0083 2403 ADD A,#0x03
C:0x0085 FE MOV R6,A
60: goto out1;
C:0x0086 8033 SJMP C:00BB
61: }else if(P13==0){
C:0x0088 20930A JB P13(0x90.3),C:0095
62: keyTmp = (i*4+4);
C:0x008B ED MOV A,R5
C:0x008C 25E0 ADD A,ACC(0xE0)
C:0x008E 25E0 ADD A,ACC(0xE0)
C:0x0090 2404 ADD A,#0x04
C:0x0092 FE MOV R6,A
63: goto out1;
C:0x0093 8026 SJMP C:00BB
64: }
这种方法是我想要的结果。
第二种情况：
不进行位宏定义，直接在函数中使用
for(i=0;i<4;i++){
P1=~tmp;
if(P1^0==0){
keyTmp = (i*4+1);
goto out1;
}else if(P1^1==0){
keyTmp = (i*4+2);
goto out1;
}else if(P1^2==0){
keyTmp = (i*4+3);
goto out1;
}else if(P1^3==0){
keyTmp = (i*4+4);
goto out1;
}
tmp<<=1;
}
此时Keil的汇编结果如下：
50: for(i=0;i<4;i++){
C:0x005F E4 CLR A
C:0x0060 FD MOV R5,A
51: P1=~tmp;
C:0x0061 EF MOV A,R7
C:0x0062 F4 CPL A
C:0x0063 F590 MOV P1(0x90),A
52: if(P1^0==0){
C:0x0065 E590 MOV A,P1(0x90)
C:0x0067 6401 XRL A,#0x01
C:0x0069 6009 JZ C:0074
53: keyTmp = (i*4+1);
C:0x006B ED MOV A,R5
C:0x006C 25E0 ADD A,ACC(0xE0)
C:0x006E 25E0 ADD A,ACC(0xE0)
C:0x0070 04 INC A
C:0x0071 FE MOV R6,A
54: goto out1;
C:0x0072 8050 SJMP C:00C4
55: }else if(P1^1==0){
C:0x0074 E590 MOV A,P1(0x90)
C:0x0076 600A JZ C:0082
56: keyTmp = (i*4+2);
C:0x0078 ED MOV A,R5
C:0x0079 25E0 ADD A,ACC(0xE0)
C:0x007B 25E0 ADD A,ACC(0xE0)
C:0x007D 2402 ADD A,#0x02
C:0x007F FE MOV R6,A
57: goto out1;
C:0x0080 8042 SJMP C:00C4
58: }else if(P1^2==0){
C:0x0082 E590 MOV A,P1(0x90)
C:0x0084 600A JZ C:0090
59: keyTmp = (i*4+3);
C:0x0086 ED MOV A,R5
C:0x0087 25E0 ADD A,ACC(0xE0)
C:0x0089 25E0 ADD A,ACC(0xE0)
C:0x008B 2403 ADD A,#0x03
C:0x008D FE MOV R6,A
60: goto out1;
C:0x008E 8034 SJMP C:00C4
61: }else if(P1^3==0){
C:0x0090 E590 MOV A,P1(0x90)
C:0x0092 600A JZ C:009E
62: keyTmp = (i*4+4);
C:0x0094 ED MOV A,R5
C:0x0095 25E0 ADD A,ACC(0xE0)
C:0x0097 25E0 ADD A,ACC(0xE0)
C:0x0099 2404 ADD A,#0x04
C:0x009B FE MOV R6,A
63: goto out1;
C:0x009C 8026 SJMP C:00C4
64: }
变成了判断P1是否为0，与我想要的结果大相径庭！
因为这个问题，让我足足调试时间花多一个多小时呀！
哪位高手能解释下是什么原因吗？ |
楼主
标题置顶
标题高亮
