#include <LPC21xx.h>
#define LED_PIN 21
#define LED_OFF (IO0CLR=(1<<LED_PIN))
#define LED_ON (IO0SET=(1<<LED_PIN))
int main (void)
{
unsigned long i;
IO0DIR |= (1 << (LED_PIN));
for (i = 0; i < 6000000; i++);
while(1)
{
LED_ON;
for (i = 0; i < 6000000; i++);
LED_OFF;
for (i = 0; i < 6000000; i++);
}
}
以上是源程序，以下是Disassembly窗口的内容
239: Vectors LDR PC, Reset_Addr
0x00000000 E59FF018 LDR PC,[PC,#0x0018]
240: LDR PC, Undef_Addr
0x00000004 E59FF018 LDR PC,[PC,#0x0018]
241: LDR PC, SWI_Addr
0x00000008 E59FF018 LDR PC,[PC,#0x0018]
242: LDR PC, PAbt_Addr
0x0000000C E59FF018 LDR PC,[PC,#0x0018]
243: LDR PC, DAbt_Addr
。。。。。。。。//中间省略若干行。。。。。。。
13: IO0DIR |= (1 << (LED_PIN));
0x000041C4 E59F1074 LDR R1,[PC,#0x0074]
0x000041C8 E5911008 LDR R1,[R1,#0x0008]
0x000041CC E3811602 ORR R1,R1,#0x00200000
0x000041D0 E59F2068 LDR R2,[PC,#0x0068]
0x000041D4 E5821008 STR R1,[R2,#0x0008]
14: for (i = 0; i < 6000000; i++);
0x000041D8 E3A00000 MOV R0,#0x00000000
0x000041DC EA000000 B 0x000041E4
0x000041E0 E2800001 ADD R0,R0,#0x00000001
0x000041E4 E59F1058 LDR R1,[PC,#0x0058]
0x000041E8 E1500001 CMP R0,R1
0x000041EC 3AFFFFFB BCC 0x000041E0
15: while(1)
16: {
0x000041F0 EA000011 B 0x0000423C
17: LED_ON;
0x000041F4 E3A01602 MOV R1,#0x00200000
0x000041F8 E59F2040 LDR R2,[PC,#0x0040]
0x000041FC E5821004 STR R1,[R2,#0x0004]
18: for (i = 0; i < 6000000; i++);
0x00004200 E3A00000 MOV R0,#0x00000000
0x00004204 EA000000 B 0x0000420C
0x00004208 E2800001 ADD R0,R0,#0x00000001
0x0000420C E59F1030 LDR R1,[PC,#0x0030]
0x00004210 E1500001 CMP R0,R1
0x00004214 3AFFFFFB BCC 0x00004208 |
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