This page (revision-7) was last changed on 03-Feb-2023 15:21 by Eli Simpson 

This page was created on 07-Feb-2011 14:47 by Gromit

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Version Date Modified Size Author Changes ... Change note
7 03-Feb-2023 15:21 28 KB Eli Simpson to previous removed extraneous "."
6 25-Nov-2021 11:39 28 KB Eli Simpson to previous | to last Changed 1 to I in keyword FI (probably a OCR error)
5 07-Feb-2011 15:31 28 KB Gromit to previous | to last
4 07-Feb-2011 15:21 21 KB Gromit to previous | to last
3 07-Feb-2011 14:59 14 KB Gromit to previous | to last
2 07-Feb-2011 14:48 14 KB Gromit to previous | to last
1 07-Feb-2011 14:47 14 KB Gromit to last

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At line 7 changed one line
!!!A New Language für the Atari!
!!!A New Language for the Atari!
At line 15 changed one line
AND Fl OR UNTIL = (
AND FI OR UNTIL = (
At line 51 changed one line
Most of the elements in an __Action!__ program are delimited by space characters - as many as you like! You don't have to keep track of line numbers, semicolons, brackets or any other nuisances that can make you feet more like a bookkeeper than a programmer. Just follow a few simple rules regarding commas and parentheses, and you're all set. __Action!'s__ modern design encourages a wide-open style of program composition, with plenty of freedom regarding the use of blank lines, upper and lower-case characters, indentation, comments and other flourishes that improve readability and make coding more fun.
Most of the elements in an __Action!__ program are delimited by space characters - as many as you like! You don't have to keep track of line numbers, semicolons, brackets or any other nuisances that can make you feet more like a bookkeeper than a programmer. Just follow a few simple rules regarding commas and parentheses, and you're all set. __Action!__'s modern design encourages a wide-open style of program composition, with plenty of freedom regarding the use of blank lines, upper and lower-case characters, indentation, comments and other flourishes that improve readability and make coding more fun.
At line 63 changed one line
__Action!'s__ editor uses your TV as a virtual window into a text area that can extend well beyond the edges of the screen. Unlike the standard Atari screen editor, you can type up to 240 characters on a single line with no cursor wraparound. How? When your cursor reaches the right edge of the screen, the line you're working on (and ''only'' that line) starts to coarse-scroll to the left. You can keep right on typing until a buzzer informs you that you've reached the rightmost position in that line - the right "edge" of the text window. Move your cursor back towards the left, and the line scrolls to the right until you hit the left edge of the window. This design neatly eliminates the usual confusion between "logical" and "physical" lines of text.
__Action!__'s editor uses your TV as a virtual window into a text area that can extend well beyond the edges of the screen. Unlike the standard Atari screen editor, you can type up to 240 characters on a single line with no cursor wraparound. How? When your cursor reaches the right edge of the screen, the line you're working on (and ''only'' that line) starts to coarse-scroll to the left. You can keep right on typing until a buzzer informs you that you've reached the rightmost position in that line - the right "edge" of the text window. Move your cursor back towards the left, and the line scrolls to the right until you hit the left edge of the window. This design neatly eliminates the usual confusion between "logical" and "physical" lines of text.
At line 69 changed one line
Other noteworthy capabilities of the __Action!__ editor include global search and replace, instant access to the beginning or end of a file and the ability to delete, move and copy, selected blocks of text. The block move and copy functions are implemented so nicely that I have to tell you about them. When you hit the SHIFT/DELETE keys, the line you're working on disappears, just as with the Atari screen editor. But the line isn't gone forever. It's being held in a buffer, waiting to be moved or copied to anywhere else in your text window(s). Simply move the cursor to a likely spot and hit CTRL/SHIFT/"P" (for paste) to dump the contents of the buffer. Several adjacent lines of text can be sent to the buffer by repeatedly "deleting" them with SHIFT/DELETE. __Action!__'s method of picking up and dropping blocks of text feels very natural if you're used to the Atari screen editor, and it also eliminates the annoyance of losing a line of work by accidentally hitting SHIFT/DELETE. Incidentally, you can automatically undo any changes you have made to a line of text by hitting CTRL/SHIFT/"U".before leaving the fine. Luxurious.
Other noteworthy capabilities of the __Action!__ editor include global search and replace, instant access to the beginning or end of a file and the ability to delete, move and copy, selected blocks of text. The block move and copy functions are implemented so nicely that I have to tell you about them. When you hit the SHIFT/DELETE keys, the line you're working on disappears, just as with the Atari screen editor. But the line isn't gone forever. It's being held in a buffer, waiting to be moved or copied to anywhere else in your text window(s). Simply move the cursor to a likely spot and hit CTRL/SHIFT/"P" (for paste) to dump the contents of the buffer. Several adjacent lines of text can be sent to the buffer by repeatedly "deleting" them with SHIFT/DELETE. __Action!__'s method of picking up and dropping blocks of text feels very natural if you're used to the Atari screen editor, and it also eliminates the annoyance of losing a line of work by accidentally hitting SHIFT/DELETE. Incidentally, you can automatically undo any changes you have made to a line of text by hitting CTRL/SHIFT/"U" before leaving the fine. Luxurious.
At line 99 changed 2 lines
[#1]
%*Jim Gilbreath, "A High-Level Language Benchmark." ''Byte'', VI, 9 (September 1981), pp. 180-198.
{{{Listing 4.
10 REM * ERATOSTHENES SIEVE
11 DIM FLAG$(8191)
12 POKE 559,0
13 POKE 19,0:POKE 20,0
14 COUNT=0
15 FOR I=1 TO 8191
16 FLAG$(I,I)="T"
17 NEXT I
18 FOR I=0 TO 8190
19 IF FLAG$(I+1,I+1)="F" THEN 27
20 PRIME=I+I+3
21 K=I+PRIME
22 if K>8190 THEN 26
23 FLAG$(K+1, K+1)="F"
24 K=K+PRIME
25 GOTO 22
26 COUNT=COUNT+1
27 NEXT I
28 TIME=PEEK(20)+256*PEEK(19)
29 POKE 559,34
30 ? COUNT;" PRIMES IN"
31 ? TIME;" JIFFIES"
}}}
Although I love standards, I don't like the __Sieve__. It's not easy for beginners to understand, it takes too long (in BASIC, anyway), and it doesn't test the Atari under real-world conditions, with lots of 6502 processor time being "stolen" by Antic for video DMA. I wanted a benchmark that anybody could appreciate, operating under the kind of DMA conditions an Atari program is likely to find itself up against.
Back in Issue 11, I devised a little program that fills a GRAPHICS 24 screen with color, one byte (eight pixels) at a time. It was used to compare a couple of BASIC compilers at the time, but it's equally valid in any run-time environment. My definitive BASIC implementation of this test appears in __Listing 5__. __Screen Fill__, as the program shall henceforth be known, executes in 4.025 jiffies or about 67 seconds on a 48K 800. (Again, improvements are possible, but for the sake of clarity let's stick to __Listing 5__.) I'll be using __Screen-Fill__ in conjunction with the __Sieve__ to judge the performance of every new language I review from now on. So let it be written; so let it be done.
{{{Listing 5.
10 REM * SCREEN-FILL BENCHMARK
11 GRAPHICS 24
12 POKE 19,0:POKE 20,0
13 SCREEN=PEEK(88)+256*PEEK(89)
14 FOR I=0 TO 31
15 FOR J=0 TO 239
16 POKE SCREEN+J,255
17 NEXT J
18 SCREEN=SCREEN+240
19 NEXT I
20 TIME=PEEK(20)+256*PEEK(19)
21 GRAPHICS 0
22 PRINT TIME;" JIFFIES"
}}}
OSS includes a implementation of the __Sieve__ benchmark in their Action! documentation. I rewrote the code slightly to make it match my BASIC implementation more closely; the modified program is shown in __Listing 6__. It executes in 89 jiffies or just under a second and a half. I'll save you a calculation by pointing out that the __Sieve__ runs about 219 times faster in __Action!__ than it does in Atari BASIC.
{{{Listing 6.
BYTE RTCLOK=20, ; addr of sys timer
SDMCTL=559 ; DMA control
BYTE ARRAY FLAGS(8190)
CARD COUNT,I,K,PRIME,TIME
PROC SIEVE()
SDMCTL=0 ; shut off Antic
RTCLOK=0 ; only one timer needed
COUNT=0 ; init count
FOR I=0 TO 8190 ; and flags
DO
FLAGS(I)='T
OD
FOR I=0 TO 8190
DO
IF FLAGS(I)='T THEN
PRIME=I+I+3
K=I+PRIME
WHILE K<=8190
DO
FLAGS(K)='F
K==+PRIME
OD
COUNT==+1
FI
OD
TIME=RTCLOK ; get timer reading
SDMCTL=34 ; restore screen
PRINTF("%E %U PRIMES IN",COUNT)
PRINTF("%E %U JIFFIES",TIME)
RETURN
}}}
Unconvinced? __Listing 7__ is an __Action!__ implementation of __Screen-Fill__. This demanding little gem executes in 32 jiffies (slightly more than half a second), or 126 times faster than its BASIC counterpart under maximum DMA handicap. And if you cheat by replacing the nested FOR-TO loops with an _Action!_, SETBLOCK procedure in the form:
{{{SETBLOCK(SCREEN,7680,255)}}}
you'll obtain an execution time of just five jiffies. This is essentially the same amount of time it takes the equivalent machine-language code to do the same job. No other high-level Atari language that I am aware of can match this kind of speed performance.
{{{Listing 7.
BYTE RTCLOK=20, ; addr of sys timer
SAVMSCL=88, ; lsb of screen addr
SAVMSCH=89, ; msb
I,J,TIME ; declare variables
CARD SCREEN
PROC BENCH()
GRAPHICS(24)
RTCLOCK=0
SCREEN=SAVMSCL+256*SAVMSCH
FOR I=0 TO 31
DO
FOR J=0 TO 239
DO
POKE(SCREEN+J,255)
OD
SCREEN==+240
OD
TIME=RTCLOK
GRAPHICS(0)
PRINTF("%E %U JIFFIES",TIME)
RETURN
}}}
!!Pulling the wings off a butterfly.
Once I got a taste of __Action!__'s dizzying speed, I had to find out what was going on inside that demonic little cartridge. So I used the W (write object code) option of the __Action!__ monitor to send a copy of the compiled __Screen-Fill__ benchmark to a disk file. Then I read it back into Ralph Jones' __Ultra Disassembler__ (published by Adventure International), massaged the labels and commented the code to make it correspond to the __Action!__ source text, line by line. The result appears in __Listing 8__.
Assembly programmers will appreciate the extraordinary efficiency of the __Action!__ compiler. The code in __Listing 8__ is totally non-recursive. It uses no special stacks or indirect pointers to control the flow of execution, just pure in-line machine code with an occasional JSR into a cartridge library routine. This is "native mode" compilation at its best: simple, clean, and very, very swift. The output of a typical C or Pascal compiler looks like spaghetti by comparison.
Because compiled __Action!__ programs refer to subroutines that reside inside the __Action!__ cartridge, you can't run a program without the cartridge in place. This may come as a disappointment to users who want to give copies of their latest __Action!__ game to friends who don't have __Action!__ OSS plans to remedy this situation by offering a Personal Run-Time Package to licensed __Action!__ users for around $30. It's a utility that will let you turn any __Action!__ program into a self-standing entity that will run with no help at all from the __Action!__ cartridge, thank you. A commercial run-time package will also be offered for a one-time licensing fee of approximately $300. Both may be available by the time you read this; contact OSS directly for more information.
Another $30 will get you OSS's Programmer's Aid Disk (PAD), a collection of demonstration programs and library routines that wouldn't fit into the already crowded __Action!__ cartridge. The libraries include badly-needed support for player/missile graphics, memory management and floating point math, precisely the weaknesses I noted above. The demo programs are very instructive and help to clarify some of the obscure features of the language. You even get a full-blown game program, written in __Action!__ by our very own Joel Gluck.
The PAD squarely addresses many of the shortcomings of the __Action!__ cartridge and documentation, and is an absolute must for all serious owners of the Action! system. In fact, this material ought to be included with every new system sold, even if it means bumping up the price a bit.
!!You can bank on it.
The 16K __Action!__ "SuperCartridge" is a technically interesting device in and of itself. It employs a hardware technique called bank-selecting to make itself "look" like an 8K cartridge. This gives you access to the 8K of RAM between $8000-$9FFF that is de-selected and thus rendered useless by a conventional 16K cartridge, such as __AtariWriter__.
The bottom half of the SuperCartridge ($A000- $AFFF) is divided into three independently addressable 4K banks of ROM, which are automatically switched in and out depending on what part of the system is in use. If your Atari has 48K or more memory, it's even possible to address the 4K bank of RAM that resides "under" this half of the cartridge. OSS's new __DOS XL__ operating system takes advantage of this capacity in a most ingenious manner. Look for a report in a future issue.
The bank-select cartridge is a nearly ideal home for Atari software. It gives the cartridge designer a full 16K to work with, enough room for plenty of bells and whistles. It gives the user an instant-loading, highly reliable environment with up to 40K of workspace. And because three of the memory banks occupy the same 4K address range, a bank-select cartridge is very difficult to pirate. Let's hope that more manufacturers start taking advantage of bank-selecting to enhance the value and security of their products.
!!Advice and admiration.
I'm sorry to report that the ''Action! Reference Manual'' doesn't do the language justice. In a commendable attempt to satisfy beginners and experts alike, the ''Manual'' suffers from lack of confidence, uncertain organization and a shortage of good, hard technical data. Thank goodness for the numerous sample programs, which communicate a lot more about the system than the text surrounding them.
Having once written the manual for a new (and mercifully obscure) programming language, I can appreciate the difficulties involved in deciding how much needs to be said, to whom, and in what order. Nevertheless, a new language can only be as good as its documentation. Until somebody sits down, rolls up his or her sleeves and writes an authoritative book about __Action!__, it will have a hard time attaining the wide acceptance it so obviously deserves. I conclude this diatribe by acknowledging that the latest edition of the ''Reference Manual'' (in the small yellow notebook) shows a marked improvement over the first release.
The __Action!__ cartridge itself has gone through a couple of changes since its first appearance in August 1983. You can tell which version you have by using the "?" (display memory) command in the monitor to examine cartridge address $B000. If this byte equals $31 hex, you have the original Version 3.1. A value of $33 indicates Version 3.3, in which a number of minor 3.1 bugs have been corrected. The final version is 3.6 ($36 at $B000), which should be ready soon after you read this. OSS has always been very good about maintaining their products, so you shouldn't have any trouble getting an upgrade if you need one. Consult OSS for prices and availability.
I hope my kvetching about the documentation doesn't scare you away. If sensible, structured code and edge-of-the-art speed are what you crave in a high-level language, __Action!__ is exactly what you need. OSS's hideous orange cartridge joins the ranks of __valFORTH__, __Omnimon!__, __ABC__ and __MAC/65__ as one of the most valuable development tools ever published for the Atari. Congratulations and thanks to Clint Parker and OSS for bringing us such an advanced product. You can expect to see plenty of support for this exciting new language in future issues of __ANALOG__.
{{{Listing 8.
0100 ; DISASSEMBLY OF COMPILED
0110 ; ACTION! SCREEN-FILL
0120 ; BENCHMARK (LISTING 7)
0130 ; -----------------------
0140 ;
0150 ; DEFINE ADDRESS CONSTANTS
0160 ; ------------------------
0170 RTCLOK = 20
0180 SAVMSCL = 88
0190 SAVMSCH = 89
0200 ;
0210 ; GLOBAL VARIABLE STORAGE
0220 ; -----------------------
0230 *= ORIGIN
0240 I *= *+1 ; reserve 1 byte for
0250 J *= *+1 ; each BYTE variable,
0260 TIME *= *+1
0270 SCREEN *= *+2 ; 2 bytes for CARDs
0280 ;
0290 ; PROC BENCH()
0300 ; ------------
0310 JMP START
0320 ;
0330 ; If our procedure used local variables,
0340 ; they would have been stored here.
0350 ; That's why the above JMP is included.
0360 ;
0370 ; GRAPHICS(24)
0380 ; ------------
0390 START
0400 LDA #24
0410 JSR GRAPHICS
0420 ;
0430 ; RTCLOK=0
0440 ; --------
0450 LDY #0
0460 STY RTCLOK
0470 ;
0480 ; SCREEN=SAVMSCL+256*SAVMSCH
0490 ; --------------------------
0500 LDA #0
0510 STA TEMP1+1
0520 LDA SAVMSCH ; move SAVMSCH into
0530 STA TEMP1 ; TEMP1
0540 LDA # >256 ; msb of multiplier
0550 TAX
0560 LDA # <256 ; lsb
0570 JSR MULTIPLY
0580 STA TEMP4
0590 TXA ; save (256*SAVMSCH)
0600 STA TEMP4+1 ; into TEMP4
0610 ;
0620 CLC
0630 LDA SAVMSCL ; add SAVMSCL to
0640 ADC TEMP4 ; (256*SAVMSCH) and
0650 STA SCREEN ; store in SCREEN
0660 LDA #0
0670 ADC TEMP4+1
0680 STA SCREEN+1
0690 ;
0700 ; FOR I=0 TO 31 DO
0710 ; ----------------
0720 LDY #0
0730 STY I ; init I-loop
0740 ILOOP
0750 LDA #31
0760 CMP I ; reached limit yet?
0770 BCS JINIT ; no - do another J-loop
0780 JMP GETIME ; else get timing
0790 ;
0800 ; FOR J=0 TO 239 DO
0810 ; -----------------
0820 JINIT
0830 LDY #0
0840 STY J ; init J-loop
0850 JLOOP
0860 LDA #239
0870 CMP J ; reached limit yet?
0880 BCS DOPOKE ; no - poke another byte
0890 JMP ADD240 ; else update screen
0900 ;
0910 ; POKE(SCREEN+J,255)
0920 ; ------------------
0930 DOPOKE
0940 CLC
0950 LDA SCREEN ; add SCREEN to
0960 ADC J ; J, and
0970 STA TEMP2 ; save in TEMP2
0980 LDA SCREEN+1
0990 ADC #0
1000 STA TEMP2+1
1010 ;
1020 LDY #255
1030 LDX TEMP2+1
1040 LDA TEMP2 ; poke (SCREEN+J) with
1050 JSR POKE ; a 255
1060 ;
1070 ; OD (for J loop)
1080 ; ---------------
1090 INC J
1100 JMP JLOOP
1110 ;
1120 ; SCREEN==+240
1130 ; ------------
1140 ADD240
1150 CLC
1160 LDA SCREEN ; add SCREEN and
1170 ADC #240 ; 240; store result
1180 STA SCREEN ; in SCREEN
1190 LDA SCREEN+1
1200 ADC #0
1210 STA SCREEN+1
1220 ;
1230 ; OD (for I loop)
1240 ; ---------------
1250 INC I
1260 JMP ILOOP
1270 ;
1280 ; TIME=RTCLOK
1290 ; -----------
1300 GETIME
1310 LDA RTCLOK
1320 STA TIME
1330 ;
1340 ; GRAPHICS(0)
1350 ; -----------
1360 LDA #0
1370 JSR GRAPHICS
1380 ;
1390 ; PRINTF("%E %U JIFFIES",TIME)
1400 ; ----------------------------
1410 JMP OVER ; skip over in-line string
1420 STRING
1430 .BYTE 13 ; length of string
1440 .BYTE "%E %U JIFFIES"
1450 OVER
1460 LDA #0 ; msb of TIME
1470 STA TEMP3 ; into TEMP3
1480 LDY TIME ; lsb into Y
1490 LDX # >STRING ; msb of string addr
1500 LDA # <STRING ; lsb
1510 JSR PRINTF
1520 ;
1530 ; RETURN
1540 ; ------
1550 RTS ; from procedure
1560 ;
1570 RTS ; back to Action! monitor
}}}
[#1]*Jim Gilbreath, "A High-Level Language Benchmark." ''Byte'', VI, 9 (September 1981), pp. 180-198.
This page (revision-7) was last changed on 03-Feb-2023 15:21 by Eli Simpson  Top