;// ____________________________________________________________________
;//
;// Copyright (c) 2002, Andrew N. Sloss, Dominic Symes, Chris Wright
;// All rights reserved.
;// ____________________________________________________________________
;// 
;// NON-COMMERCIAL USE License
;// 
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;// modification, are permitted provided that the following conditions 
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;// 1. For NON-COMMERCIAL USE only.
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;// 4. All advertising materials mentioning features or use of this 
;//    software must display the following acknowledgement:
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;//    This product includes software developed by Andrew N. Sloss,
;//    Chris Wright and Dominic Symes. 
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        AREA    |.text|, CODE, READONLY
        
        EXPORT  sumof
        
N       RN 0    ; number of elements to sum
sum     RN 1    ; current sum
        
        ; int sumof(int N, ...)
sumof
        SUBS    N, N, #1        ; do we have one element
        MOVLT   sum, #0         ; no elements to sum!
        SUBS    N, N, #1        ; do we have two elements
        ADDGE   sum, sum, r2
        SUBS    N, N, #1        ; do we have three elements
        ADDGE   sum, sum, r3
        MOV     r2, sp          ; top of stack
loop
        SUBS    N, N, #1        ; do we have another element
        LDMGEFD r2!, {r3}       ; load from the stack
        ADDGE   sum, sum, r3
        BGE     loop
        MOV     r0, sum
        MOV     pc, lr          ; return r0
        
        END