C语言: [Key1_On是定义在内部RAM中的位变量]
if(Key1_On==0)
{}
if(Key1_On==1)
{}
编译后的汇编:
140: if(Key1_On==0)
0x0000001D: BTS0 0x20.2
0x0000001E: JMP 0x001F
141: {}
142: if(Key1_On==1) ;下面一大堆代码怎么来的?
0x0000001F: MOV A, 0x20
0x00000020: B0MOV 0x07, A
0x00000021: RRCM 0x07
0x00000022: RRCM 0x07
0x00000023: MOV A, #3fh
0x00000024: AND 0x07, A
0x00000025: B0MOV A, 0x07
0x00000026: AND A, #01h
0x00000027: SUB A, #01h
0x00000028: B0BTS1 PFLAG.0
0x00000029: JMP 0x002A
143: {}
C语言改成:
if(Key1_On==0)
{
if(Key1_On)
{}
编译后的汇编:
140: if(Key1_On==0)
0x0000001D: BTS0 0x20.2
0x0000001E: JMP 0x001F
141: {}
142: if(Key1_On)
0x0000001F: BTS1 0x20.2
0x00000020: JMP 0x0021
143: {}
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为什么会这样?? |
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楼主
