AREA RESET, CODE, READONLY
ENTRY
CODE32
START
; 配置按键的IO端口为输入
LDR R0, =0x56000050
LDR R1, =0x00000000
STR R1, [R0]
; 配置LED的IO端口为输出
LDR R2, =0x56000010
LDR R3, =0x00015400
STR R3, [R2]
; 熄灭全部LED
LDR R2, =0x56000014
LDR R3, =0x000001e0
STR R3, [R2]
LOOP
; 读取按键状态
LDR R0, =0x56000054
LDR R1, [R0]
; LED初始状态为熄灭
LDR R3, =0x000001E0
;判断K1是否按下
TST R1, #0x00000002
BICEQ R3, #0x00000020 ;5
;判断K2是否按下
TST R1, #0x00000010
BICEQ R3, #0x00000040 ;6
;判断K3是否按下
TST R1, #0x00000004
BICEQ R3, #0x00000080 ;7
;判断K4是否按下
TST R1, #0x00000001
BICEQ R3, #0x00000100 ;8
;控制LED显示
STR R3, [R2]
B LOOP
END
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