test3.txt

ARM综合板子分时电度器计算电价

.global _start
.text
.equ	time1, 6              	/* Number of entries in jump table */
.equ    time2, 22

_start:
        MOV     r0, #0  		/*  set up the three parameters */
        MOV     r1, #10			/*R1中是由时钟传来的时刻（小时，不计分钟），*/
        MOV     r2, #20			/*R2中为6时至22时用电度数20（整数，动态增加）*/
        MOV     R3,#30       /*R3中为22时至次日6时用电度数30（整数，动态增加），*/
        MOV     R4,#4		    /*R4中为每度电的价格（4元），*/
        MOV     R8,#4
        MOV     R9,#2
        MOV     R10,#0x00000003
        BL      arithfunc   /*  call the function   BL:Branch with link */

stop:
        B		stop

arithfunc:                       /*  label the function */
        MLA R7,R2,R8,R0
        MLA R6,R3,R9,R7
        STMIA r10,{R6}
        CMP     r1, #time1        /*  Treat function code as unsigned integer */
        BLS     DoHalf           /*  If code is <=6 then do operation 0. */
        CMP     R1,#time2
        BHS     DoHalf
        BL			DoFull
				
        ADR     r3, JumpTable   /*  Load address of jump table */
        LDR     pc, [r3,r0,LSL#2]	/*  Jump to the appropriate routine */

JumpTable:
        .long     DoFull
        .long     DoHalf

DoFull:
        MOV     R5,#4
        MOV     pc,lr

DoHalf:
	MOV     R5,#2
    MOV     pc,lr 

.end							/*  mark the end of this file */