--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/alib/dec_bin.as	Sat Jan 26 17:18:24 2013 -0600
@@ -0,0 +1,110 @@
+****************************************
+
+* DECIMAL to BINARY conversion routine
+
+* OTHER MODULES NEEDED: DECTAB$, IS_TERMIN
+
+* ENTRY: X = start of asci decimal string terminated by
+*            a space, comma, CR or null.
+
+* EXIT: D = binary value
+*       CC carry set if error (too large, not numeric)
+*       Y = terminator or error char.
+
+ nam Convert Decimal String to Binary
+ ttl Assembler Library Module
+
+
+ section .bss
+nega rmb 1
+ endsect
+
+ section .text
+
+DEC_BIN:
+ clra set result to 0
+ clrb
+ pshs a,b,x
+ leas -1,s temp variable
+
+ clr nega,u
+ ldb ,x+
+ cmpb #'-
+ bne decbn15
+ stb nega,u
+decbn1
+ LDB ,X+ get a digit
+decbn15
+ LBSR IS_DIGIT
+ bne decbn3 end of string...
+ INCA bump string len
+ BRA decbn1 loop for whole string
+
+decbn3
+ lbsr IS_TERMIN valid terminator?
+ bne error
+
+ok
+ TSTA length = 0?
+ BEQ error yes, error
+ CMPA #6 more than 6 chars?
+ BHI error yes, error
+
+ ldx 3,s get start of string again
+
+ PSHS A
+ lda ,x
+ cmpa #'-
+ bne decbn35
+ leax 1,x
+decbn35 
+ LDA #5 max length
+ SUBA ,S+ adjust for offset
+ ASLA 2 bytes per table entry
+ LEAY DECTAB$,PCR addr of conversion table
+ LEAY A,Y add in offset for actual len
+
+decbn4
+ LDA ,X+ get a digit
+ SUBA #$30 strip off ASCII
+ BEQ decbn6 zero, skip
+ sta ,s save digit=# of adds
+ LDD 1,S get binary data
+
+decbn5
+ ADDD ,Y add in table value
+ BCS error past 0, too big
+ DEC ,S count down digit size
+ BNE decbn5 loop til 0
+ STD 1,S save binary data
+
+
+decbn6
+ LEAY 2,Y next entry
+ tst 1,y end of table?
+ BNE decbn4 loop til done
+ clr ,s+ clean up and clear carry
+ bra exit
+
+
+error
+ clr 0,s force data = 0
+ clr 1,s
+ com ,s+ clean up and set carry
+
+exit
+ tfr x,y end of string/error char
+ puls a,b,x
+ bcs leave
+ tst nega,u
+ beq leave
+ subd #$0001
+ coma
+ comb
+ andcc #$FE
+leave
+ rts
+
+
+ endsect
+