While programing dMetronome I had to learn a few things. How to divide the number of DLIs in a minute by the number of DLIs to get beats per min. I finally got to the point where I could use the Diamond Macro Divide to handle the division and as long as I kept the answer to one byte I was fine but there were many tribulations along the way.

 

My first revelation was that the macro needed the numbers to be passed to them. Many of the d-macros pass the address pointer to W0 to W7 but not the divide and multiply macros. They require that the numbers be passed to the macro. The answer is much different when dividing two numbers or two address .

 

The macros were changed to accept 2 addresses as pointers and then the macro moves the numbers at those addresses into W4 and W5. The answer of the division will be located at W6 and W7.

 

Original DIVIDE Macro

8630 ;

8640 .MACRO DIVIDE

8650 LDA # <%1 ;NUMBER

8660 STA W4

8670 LDA # >%1

8680 STA W4+1

8690 LDA # <%2 ;DIVISOR

8700 STA W5

8710 LDA # >%2

8720 STA W5+1

8730 LDA #DIVIDE

8740 JSR DIAMOND

8750 .ENDM

8760 ;

 

Modified Macro

8630 ;

8635 ;MODIFIED TO LOAD NUM FROM ADDR.

8636 ;KPACK - 5/16/2018

8640 .MACRO DIVIDE

8650 LDA %1 ;NUMBER

8660 STA W4

8670 LDA %1+1

8680 STA W4+1

8690 LDA %2 ;DIVISOR

8700 STA W5

8710 LDA %2+1

8720 STA W5+1

8730 LDA #DIVIDE

8740 JSR DIAMOND

8750 .ENDM

8760 ;

 

This would seem to make more sense but luckily on the first try I used 2 numbers that yielded erroneous results. The following program was used to test the modified macro. Change the values for NUM01 and NUM02, compile to evaluate the result.

 

Test Program

10 ;THIS PROGRAM IS TO TEST CHANGES

20 ;MADE TO THE DIAMOND MACRO LIBRARY

30 ;

40 ;MACRO NOW LOADS NUMBERS AT ADDR.

50 ;NOT NUMBERS

60 ; DOUBLE BYTE MATH ON TWO NUMBERS.

70 ; RESULTS PRINTED IN HEX.

80 ;

90 ;

0100 .OPT NO LIST

0110 .OPT OBJ

0120 *= $2200

0130 .INCLUDE #D2:DMACRO01.M65

0140 ;

0150 NUM01 .WORD 1211

0160 NUM02 .WORD 37

0180 DIVRST .WORD 0 ; DIV RESULTS

0190 DIVREM .WORD 0 ; DIV REMAINDER

0200 DVAR .WORD 0 ;Used to hold print variable

0210 HEXSTG .BYTE "$ ",255 ; 4 spaces for double byte

0220 HEXCHR .BYTE $30,$31,$32,$33,$34

0230 .BYTE $35,$36,$37,$38,$39

0240 .BYTE $41,$42,$43,$44,$45

0250 .BYTE $46

0260 ;

0270 START INIT 0

0280 DIVIDE NUM01,NUM02

0290 LDA W6 ;STORE RESULTS

0300 STA DIVRST

0310 LDA W6+1

0320 STA DIVRST+1

0330 LDA W7

0340 STA DIVREM

0350 LDA W7+1

0360 STA DIVREM+1

0370 LDA NUM01 ;LOAD NUM TO CONVERT

0380 STA DVAR

0390 LDA NUM01+1

0400 STA DVAR+1

0410 JSR DB2HEX

0420 SYSDRAW HEXSTG,10,20,0

0430 LDA NUM02 ;LOAD NUM TO CONVERT

0440 STA DVAR

0450 LDA NUM02+1

0460 STA DVAR+1

0470 JSR DB2HEX

0480 SYSDRAW HEXSTG,10,30,0

0490 LDA DIVRST ;LOAD NUM TO CONVERT

0500 STA DVAR

0510 LDA DIVRST+1

0520 STA DVAR+1

0530 JSR DB2HEX

0540 SYSDRAW HEXSTG,10,50,0

0550 LDA DIVREM ;LOAD NUM TO CONVERT

0560 STA DVAR

0570 LDA DIVREM+1

0580 STA DVAR+1

0590 JSR DB2HEX

0600 SYSDRAW HEXSTG,10,60,0

0610 LOOP EVENT

0620 LDA EVENTTYPE

0630 BEQ LOOP

0640 EXIT ;DIAMOND

0650 EXECDESKTOP

0660 ;

0670 ;

0680 ;CONVERT HEX TO STRING

0690 DB2HEX LDA DVAR

0700 AND #$0F

0710 TAX

0720 LDA HEXCHR,X

0730 STA HEXSTG+4

0740 LSR DVAR

0750 LSR DVAR

0760 LSR DVAR

0770 LSR DVAR

0780 LDX DVAR

0790 LDA HEXCHR,X

0800 STA HEXSTG+3

0810 LDA DVAR+1

0820 AND #$0F

0830 TAX

0840 LDA HEXCHR,X

0850 STA HEXSTG+2

0860 LSR DVAR+1

0870 LSR DVAR+1

0880 LSR DVAR+1

0890 LSR DVAR+1

0900 LDX DVAR+1

0910 LDA HEXCHR,X

0920 STA HEXSTG+1

0930 RTS

0940 ;

0950 *= $02E0

0960 .WORD START

 

This is a list of the numbers used for the tests and the results as printed to the screen.

 

Test NUM01 / NUM02 = Result Remainder

(W4) (W5) (W6) (W7)

1 $04BB $0025 $0020 $001B

2 $FFFF $0001 crash

3 $FFFF $FFFF crash

4 $B478 $C3B2 crash

5 $0000 $F2F7 $0000 $0000

6 $F2F7 $0AB4 crash

-

7 $FFFE $0002 crash

8 $0FFF $0002 $07FF $0001

-

9 $7FFF $0002 $3FFF $0001

10 $8000 $0002 crash

-

11 $0002 $7FFF $0000 $0002

12 $0002 $8000 $0000 $0002

13 $0002 $FFFF $0000 $0002

14 $7FFF $7FFF $0001 $0000

15 $75D1 $72A5 $0001 $032C

 

 

After test 6 it was noted that any number that had bit 15 set might crash Diamond 3.0. Test 7 and 8 proved that it is within the upper 4 bits of the double byte number that a problem occurred. Test 9 and 10 proved that it was bit 15 that was the problem. Tests 11 - 15 were tried to verify the crash point.

 

In conclusion I believe (at this moment in time) that the DIVIDE macro, as modified, will accept the addr-s for 2 numbers and give the proper results if:

1. The numerator (NUM01) is between 0 - 32767 ($0000 - $7FFF).
   
2. The denominator(NUM02) is a double byte number but not 0.
   

 

Disclaimer:

I have only tested the Divide Diamond function on my Diamond 3.0 cartridge. I have included the ATR with the source files so you can generate test results on your system. You'll need the MAC/65 cart.

 

div macro test.zip

 

I'm not up to delving into the Diamond Source code and will simply try to stay within the restrictions defined above. Of course, if these assumptions are incorrect I won't find out until after I click "Publish".

 

When the tests on the multiply function have been finalized a report will be issued.