ldrlabel.s

wARM兼容ARM7TDMI指令集

        AREA LDRlabel, CODE,READONLY
        ENTRY                           ; Mark first instruction

start   
        BL      func1                   ; Branch to first subroutine
        BL      func2                   ; Branch to second subroutine

stop
        MOV     r0, #0x18               ; angel_SWIreason_ReportException
        LDR     r1, =0x20026    ; ADP_Stopped_ApplicationExit
        SWI     0x123456                ; Angel semihosting ARM SWI


func1
        LDR     r0, =start              ; => LDR R0,[PC, #offset to
                                        ;                       Litpool 1]
        LDR     r1, =Darea +12  ; => LDR R1,[PC, #offset to
                                        ;                       Litpool 1]
        LDR     r2, =Darea + 6000       ; => LDR R2, [PC, #offset to
                                        ;                       Litpool 1]
        MOV     pc,lr                   ; Return

        LTORG                           ; Literal Pool 1

func2
        LDR     r3, =Darea +6000  ; => LDR r3, [PC, #offset to
                                        ;                       Litpool 1]
                                        ; (sharing with previous literal)
        ; LDR   r4, =Darea +6004        ; If uncommented will produce an
                                        ; error as Litpool 2 is out of range
        MOV     pc, lr          ; Return

Darea           % 8000          ; Clears a 8000 byte area of memory, 
                                        ; starting at the current location,
                                        ; to zero.

      END           ; Literal Pool 2 is out of
                                        ; range of the LDR instructions
                                        ; above