Converting Applesoft Basic to Atari Basic
Neater Numerical Tables
Paul N. Havey
In Neaten Up Those Messy Numerical Tables by Donald J. Taylor (Creative Computing, December, 1981), the author designed a short program, written in Applesoft, which enables the user to print numbers in a neat exponential form. While the program may be an answer to the dreams of many an Apple owner, it is of little use to still-dreaming Atari owners.
Conversion from Applesoft to Commodore or TRS-80 Basic is more direct than conversion to Atari Basic. This is because Atari Basic does not support string arrays like the others. However, with the unlimited string length capability of Atari Basic, program conversions are possible for Atari owners and, in some cases, simplified.
Included here is a translation from Applesoft Basic to Atari Basic of Taylor's exponential program. Also included is a listing of the original program for comparison. Both programs convert a number to a string which is then disassembled. The number is then reassembled by concatenation into a thousand string mantissa and exponential for the scientific notation format. Zeros and signs are inserted where needed. See Table 1 for a sample of printed output.
The variable names and time requirements for the Atari Basic version are only slightly different from the original Applesoft Basic version. Table 2 contains a list of variable names for the Atari Basic version and Table 3 contains the time and memory requirements for both versions.
The handling of string variables is one of the fundamental differences between Applesoft and Atari Basics. In Microsoft Basic (and in Applesoft) extraction or splitting a string into pieces is done by the functions MID$, RIGHT$, and LEFT$. In Atari Basic, strings are split by using a subscript or set of subscripts. For example, A$(6,12) means that the substring starts at the sixth character and ends with the twelfth. If one number is within the subscript then the subscript begins with that character and ends with the last character in the string.
Table 4 contains a list of Atari to Microsoft translations. The LEN(A$) function is the same in both types of Basic.
Atari Basic uses the LEN(A$) functions to concatenate two substrings. In Microsoft Basic, concatenation is done with a plus sign. Table 4 shows an example of each.
Microsoft Basic uses subscripts as an indication of a string array. Atari Basic, while not supporting string arrays, can simulate string arrays by using subscripts. In Atari Basic, simulated arrays that have all the same length are the most useful.
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Table 1. Sample Data Columns. |
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| Table 2. Atari version of the variable list. |
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Table 3. Atari Time and Memory Requirements. |
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| Table 4. String Operation Comparisons. |
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Program 1.
10 REM SCIENTIFIC NOTATION FORMAT 20 REM CONSTANT SIGNIFICANT DIGITS 30 REM TRUNCATOR/ROUNDER 40 REM REVISED FOR ATARI BASIC 45 REM BY PAUL HAVEY 01 DEC 82 50 REM INPUT: TWO VARIABLES 60 REM 1. X=NUMBER TO FORMAT 70 REM 2. D=SIGNIFICANT DIGITS 75 REM D-1 FOR ROUNDING 80 REM OUTPUT: ONE VARIABLE 90 REM 1. X$=FORMATTED NUMBER 100 DIM X$(20),BUF$(20),E$(3),BUFI$(10),S$(1) 110 S$=" ":IF SGN(X)=-1 THEN S$=" " 120 BUF=ABS(X):BUF$=STR$(BUF):L=LEN(BUF$) 130 IF L>4 THEN IF BUF$(L-3,L-3)="E" THEN E$=BUF$(L-2):BUF$(L-3)="0000":GOTO 230 140 IF BUF=0 THEN X$=" 0":GOTO 300 150 IF BUF<1 THEN 210 160 BUFI$=STR$(INT(BUF)) 170 E$="+0":E$(3,3)=STR$(LEN(BUFI$)-1) 180 IF BUF<10 THEN 230 190 BUF$(2,2)=".":BUF$(3,LEN(BUFI$)+1)=BUFI$(2) 200 GOTO 230 210 IF BUF$(3,3)="0" THEN E$="-02":BUF=BUF*100:BUF$=STR$(BUF):GOTO 230 220 E$="-01":BUF=BUF*10:BUF$=STR$(BUF) 230 BUF$(LEN(BUF$)+1)="00000000" 240 BUF$=BUF$(1,D+1):BUF$(2,2)="." 290 X$=S$:X$(2)=BUF$:X$(LEN(X$)+1)="E":X$(LEN(X$)+1)=E$ 300 RETURN
Program 2.
250 REM ROUNDING ROUTINE 260 BUF$(2)=BUF$(3):BUF=(VAL(BUF$)+5):BUF$=STR$(BUF):IF LEN(BUF$)=D THEN 280 270 L=ABS(VAL(E$)+1):E$(2)=STR$(L):IF L<10 THEN E$(3)=E$(2):E$(2,2)="0" 280 X$=BUF$(2):BUF$(2,2)=".":BUF$(3)=X$(1,D-2)
Program 3.
100 REM SCIENTIFIC NOTATION FORMATTER 102 REM CONSTANT SIGNIFICANT FIGURES 104 REM TRUNCATOR/ROUNDER 106 REM DONALD J. TAYLOR 108 REM JUNE 1, 1982 110 REM INPUTS REQUIRED=X AND D 112 REM X=INPUT # 114 REM D=# DIGITS FOR TRUNCATION 116 REM D-1=# DIGITS FOR ROUNDING 118 REM X$=OUTPUT 120 REM 122 S$=" ":IF SGN(X)=-1 THEN S$="-" 124 X=ABS(X):X$=STR$(X):P=LEN(X$) 126 IF P>4 THEN IF MID$(X$,P-3,1)="E" THEN P$=MID$(X$,P-2):X$=LEFT$(X$,P-4):X$=LEFT(X$,1)+"."+MID$(X$,3):GOTO 140 128 IF X=0 THEN X$=" 0":P$=" ":GOTO 164 130 IF X<1 THEN GOTO 136 132 XI$=STR$(INT(X)) 134 X$=LEFT$(XI$,1)+"."+MID$(XI$,2)+MID$(X$,LEN(XI$)+2):P$="+0"+STR$(LEN(XI$)-1):GOTO 140 136 IF MID$(X$,2,1)="0" THEN P$="-02":X$=MID$(X$,3,1)+"."+MID$(X$,4):GOTO 140 138 P$="-01":X$=MID$(X$,2,1)+"."+MID$(X$,3) 140 X$=X$+"00000000" 142 X$=LEFT$(X$,D+1) 162 X$=S$+X$+"E"+P$ 164 RETURN
Program 4.
144 REM ROUNDING ROUTINE : LINES 144-160
146 X$=LEFT$(X$,1)+MID$(X$,3)
148 X=VAL(X$)+5:X$=STR$(X)
150 IF LEN(X$)=D THEN GOTO 160
152 P=VAL(RIGHT$(P$,3))+1
154 IF SGN(P)=1 THEN GOTO 158
156 P$="-"+RIGHT$(("0"+STR$(ABS(P))),2):GOTO 160
158 P$="+"+RIGHT$(("0"+STR$(ABS(P))),2)
160 X$=LEFT$(X$,1)+"."+MID$(X$,2,D-2)
Paul T. Havey, P.O. Box 5148, Santa Monica, CA 90405.
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