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; $Id: kprdec.mac 503 2013-04-06 19:44:13Z mueller $

; Copyright 2013- by Walter F.J. Mueller 

; License disclaimer see LICENSE_gpl_v2.txt in $RETROBASE directory

;

; synchronous (polling) console print: print signed decimal number

; Call:

;   jsr  pc, kprdec

; Arguments:

;   r0: number to print

;

; r1-r5 registers preserved

;

kprdec: mov     r1,-(sp)        ; save r1,..,r3

        mov     r2,-(sp)

        mov     r3,-(sp)

        mov     r0,r2           ; setup number to convert

        bge     1$              ; if negative

        neg     r2              ; negate

        mov     #'-,r0          ; and print a '-'

        jsr     pc,kprchr

1$:     mov     #101$,r1        ; r1 points behind end of buffer

        clrb    -(r1)           ; ensure 0-termination

        movb    #'.,-(r1)       ; and trailing '.' to indicate decimal

        mov     #5,r0           ; loop over 5 digits

        tst     r2              ; number 0

        bne     2$              ; if not convert

        movb    #'0,-(r1)       ; if yes, ensure that '0' is printed

        br      3$

2$:     mov     r2,r3           ; r2 is rest to convert

        beq     3$              ; break if zero

        clr     r2              ; now (r2,r3) 32bit rest to convert

        div     #10.,r2         ; div: r2->quotient; r3->reminder

        add     #'0,r3          ; r3 is reminder, convert to char

        movb    r3,-(r1)        ; write (backwards) to buffer

        sob     r0,2$           ; go for next digit

3$:     mov     r1,r0           ; r1 now points to convered string

        jsr     pc,kprstr       ; print it

        mov     (sp)+,r3        ; restore r1,..,r3

        mov     (sp)+,r2

        mov     (sp)+,r1

        rts     pc

100$:   .blkb   7.              ; buffer

101$:                           ; end-of-buffer

        .even