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  A string bug in 1.2.8-s682 (*solved*)
Posted by: Darkstar - 2011-03-29, 02:17 AM - Forum: Bug Reports - Replies (12)

This does not work:

Code:
#Include "alloc.bas"
Declare function String$ (ByVal NumberOfChars as ubyte, ByVal Char as string) as string
Declare sub PlayScrBasic (byval SkyColor as ubyte)

Ink 7: Paper 0: Flash 0: Bright 1: Over 0: Inverse 0: Border 0: Cls
Print "Hello"

Const Black as ubyte = 0
Const Blue as ubyte = 1
Const Red as ubyte = 2
Const Magenta as ubyte = 3
Const Green as ubyte = 4
Const Cyan as ubyte = 5
Const Yellow as ubyte = 6
Const White as ubyte = 7

PlayScrBasic (Cyan)
End


Function String$ (ByVal NumberOfChars as ubyte, ByVal Char as string) as string

'Dim Chars$ as string

'Dim CharPtr as uinteger
'Dim CharsPtr as uinteger
'Dim CharsPtrDeallocate as uinteger
'CharStr
'NumberOfChars = NumberOfChars + 1
'CharsPtr = Allocate(NumberOfChars)
'Dim CharStr as string at @CharP


''CharP = @Char$
'Return "x" '@Char$

Dim i as ubyte

For i = 1 to NumberOfChars
  Chars$ = Chars$ + Char$
Next i

Return Chars$

End Function

sub PlayScrBasic (byval SkyColor as ubyte)

Dim i as ubyte
Dim Space32$ as string
Space32$ = String$(32, " ")

cls
Paper SkyColor
If SkyColor <> 0 then
  fOR i = 0 TO 12
    'Print at i, 0; String$(32, " ")
    Print at i, 0; Space32$
  Next i
End if
Space32$ = ""

Paper Green
Print at 11, 6; String$(21, " ")

FOR i = 8 TO 21
  Paper Red
  Print at i, 5; " "
  IF i > 11 THEN
    Print at i,5; String$(22, " ")
    IF i > 12 AND i < 21 THEN
      Paper Blue
      Print at i, 0; String$(5, " ")
      Print at i, 27; String$(5, " ")
    End if
  End if
Next i

Paper Yellow
Print at 21, 0; String$(5, "Û")
Print at 21, 27; String$(5, "Û")
Paper Black

end sub

However if I rem out everything that has Space32$ in it and unrem:
'Print at i, 0; String$(32, " ")'
Then it works fine and heap size does not seem to matter. If I press break
and restart the program then it fails on the second run even though it
works fine the first time if I make the changes noted above.

My bat file to compile this is as follows:
@echo off
if exist GAME.TAP del GAME.TAP
zxb Invasion.b --optimize=0 --output=GAME --tap --BASIC --autorun --org=39680 --array-base=0 --string-base=0 --heap-size=1280 --strict-bool --enable-break
ren GAME GAME.TAP

I do not trust this string handling and it would be nice to have a inbuildt
String$(NumChars, Char$) function.

Thanks,

Darkstar.

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  Sound effects?
Posted by: LTee - 2011-03-25, 09:48 AM - Forum: How-To & Tutorials - Replies (21)

Can anyone suggest how I could make some half-reasonable beeper sound effects? My initial experiments with BEEP are.... uninspiring. :-D

I was wondering if there was a tool or something that I could use to create some snazzier effects and then somehow integrate those into my ZXBasic setup? Or are there any tricks that people use to get more out of BEEP?

Thanks!

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  What's wrong with this code?
Posted by: LTee - 2011-03-24, 03:14 PM - Forum: Help & Support - Replies (4)

Okay, this is driving me mad. :-D

I wrote a little routine to 'shuffle' the numbers 1 to 10 into an array, randomly. It's not exactly the best way of doing this but it was supposed to be a quick test. Regardless, it doesn't work. Or rather, it does work - the first time you run it. The second loop of the same code never completes and I can't decide if I found a bug or if I've made a mistake.

Here's the code:

Code:
dim levelMap(10) as UBYTE

randomize
for x = 1 to 10
    cls
    generateLevelMap()
    for n = 1 to 10: print levelMap(n): next n
    pause 0
next x

SUB generateLevelMap()
    dim lm as UBYTE
    dim lmPos as UBYTE = 0
    
    'clear the map first
    for lm = 1 to 10
        levelMap(n) = 0
    next lm
    
    'debug code to print the map, to make sure it's empty
    print
    for lm = 1 to 10
        print levelMap(n);",";
    next lm
    print
    pause 0
    
    'now fill it randomly
    print
    for lm = 1 to 10
        do
            'get a random position in the array
            lmPos = int(rnd * 10) + 1
            
            'debug code to print the number we randomly picked
            print lmPos;",";
            
            'debug code to print the array element if it ISN'T empty
            if levelMap(lmPos) <> 0 then
                print ink 2;levelMap(lmPos);",";
            end if
            
        loop until levelMap(lmPos) = 0
        
        'write the current number into the empty random element
        levelMap(lmPos) = lm
        
        'debug code to show that we handled this number okay
        print inverse 1;lm
        
    next lm
    
    pause 0
    cls
END SUB

I've stuck a load of debug info in there so that you can see what it's doing.

Basically it does this:
1. Clear the array to all zeroes
2. For each number, 1 to 10....
3. Look in a random array position to see if it's zero.
3a. if it isn't, loop around to 3 and try a different one
3b. if it is, write the number into that array position and move on to the next number
4. The result should be the numbers 1 to 10 in a random order in the array, after a variable number of iterations.

First run, no problem.

Second run, although the debug code shows that the array was cleared, the do...loop until loop never completes - by the time it's checking the array within that loop it contains the OLD values again, despite me having zeroed them out just a few seconds earlier.

Am I missing an obvious goof? :-D

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  Effects of running out of memory
Posted by: LTee - 2011-03-23, 03:03 PM - Forum: Help & Support - Replies (4)

I just added another (hopefully the final!) screen to my game and after compilation it locked up at the menu screen. I suspect that this is because of a lack of memory - my compiled code is now 28932 bytes long, so starting at the default of 32768 that takes me up to 61700. The heap is 4k still, yes? So there's not actually enough space to allocate it, I suspect. Compiling with -O2 took the size down a little and allowed it to run for longer, but I was still getting lockups.

I fixed this by moving the ramtop up to 30000 and now it seems fine. However, is there any way for me to be sure that this is enough space? And is there anything I should watch out for now that I've had to use some contended memory?

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  Try this for faster multiply?
Posted by: britlion - 2011-03-23, 01:26 AM - Forum: Wishlist - Replies (1)

(where /should/ I be putting this sort of thing?)

Plug this in for mul16.asm

Code:
__MUL16:    ; Mutiplies HL with the last value stored into de stack
            ; Works for both signed and unsigned

        PROC

        LOCAL __MUL16LOOP1
                LOCAL __MUL16NOADD1
        LOCAL __MUL16LOOP2
                LOCAL __MUL16NOADD2

        
        ex de, hl
        pop hl        ; Return address
        ex (sp), hl ; CALLEE caller convention

;;__MUL16_FAST:    ; __FASTCALL ENTRY: HL = 1st operand, DE = 2nd Operand
;;        ld c, h
;;        ld a, l     ; C,A => 1st Operand
;;
;;        ld hl, 0 ; Accumulator
;;        ld b, 16
;;
;;__MUL16LOOP:
;;        sra c    ; C,A >> 1  (Arithmetic)
;;        rra
;;
;;        jr nc, __MUL16NOADD
;;        add hl, de
;;
;;__MUL16NOADD:
;;        sla e
;;        rl d
;;            
;;        djnz __MUL16LOOP

__MUL16_FAST:
        ld b, 8
        ld a, d
        ld c, e
        ex de, hl
        ld hl, 0

__MUL16LOOP1:
        add hl, hl  ; hl << 1
        ;sla c
        rla         ; a,c << 1
        jr nc, __MUL16NOADD1
        add hl, de

__MUL16NOADD1:
        djnz __MUL16LOOP1

        ld a,c
        ld b,8

__MUL16LOOP2:
        add hl, hl  ; hl << 1
        rla         ; a,c << 1
        jr nc, __MUL16NOADD2
        add hl, de

__MUL16NOADD2:
        djnz __MUL16LOOP2



        ret    ; Result in hl (16 lower bits)

        ENDP

I think it saves on average about 110 T states per multiply, according to my tests. If I counted correctly, it's 10 bytes longer.

Why it's faster:

SLA C is a long slow opcode, compared to just doing the RLA. It's faster to loop twice and roll the A register round the two halves than it is to roll the 16 bit pair.

Also in this case, JR is a better choice than the original JP instruction. Not only is it a byte shorter, but it's faster on average. Probably.

16 JP NC instructions = 160 T states.
JR is 7 if condition fails, 12 if it passes. We can assume that for bits, half will be 1 and half will be 0. So that's an average of (8*12)+(8*7)=156 T states. It's worth saving the byte; which compensates for a double loop being a few extra bytes.

Could also probably shave a little time by using dec b && jp nc _mul16loop since that will jump most times. Probably not worth the bytes. Having two short loops actually speeds up the DJNZ a little too Smile

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  Run Time error in Footy code.
Posted by: britlion - 2011-03-19, 05:16 PM - Forum: Bug Reports - Replies (5)

1.2.8-s644 Still isn't running correctly.

My half build football manager program gives an out of memory error at some early string handling. Goes right past that if compiled with 1.26.

I tried to attach a file, here, but couldn't.

With 1.2.8-s644 this breaks at line 438, just after the print 2. With 1.26 it works (it breaks later. Haven't investigated that).

Always compiled with --debug-array --debug-memory (not with O3).

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  fixed is broken (*solved*)
Posted by: britlion - 2011-03-18, 12:37 AM - Forum: Bug Reports - Replies (7)

Code:
CLS

#include <input.bas>
dim num AS FIXED
value$=input(8)
cls
print value$
num=VAL(value$)

print num
print num/2
print ln (num)

The last line - ln(num) breaks it. Without that line it compiles, but gives nonsensical answers. I think this is the reason why my fSin benchmark isn't compiling. fSin works with fixed point numbers.

There's an issue with input / strings as well though:

Code:
CLS

#include <input.bas>

dim num AS FIXED

value$=input(8)
cls
print value$

Compiles, but gave an out of screen error for me.

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  Loosing "print8.asm" (solved-not a bug)
Posted by: compiuter - 2011-03-14, 07:05 PM - Forum: Help & Support - Replies (2)

In my netbook I overwrite your new version 128r573 with old 126 and run my program. This file seems to be loosed.

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  Labels as byte values in inline assembly
Posted by: britlion - 2011-03-13, 02:47 PM - Forum: Help & Support - Replies (3)

If I had code that wanted to make a jump table, and still be able to compile it such that it can move around, how can I do this?

That is, I want something like

jump_table:
defb routine1
defb routine2
defb routine3


routine1:
<code>
ret

routine2:
<code>


routine3:
<code>


The design calls for a jp (hl). I could probably code around it, but I'm wondering how I could get label locations into the actual bytes compiled?

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  Bug or Feature?
Posted by: LCD - 2011-03-10, 06:39 PM - Forum: Help & Support - Replies (8)

Hi Boriel, I ran into following Problem:

Code:
print at 17,0;(peek 3)*9
gives me back 247. Why is this a Problem? PEEK 3 is 255, so (PEEK 3)*9 should be calculated as 255*9=2295, so it looks like the result of this calculation is stored in UBYTE. No problem because PEEK gives back UBYTE, but a multiplication is a little bit more problematic.
Code:
dim c1 as uinteger
c1=peek(adr)
print c1*9
Works, but
Code:
dim c1 as ubyte
c1=peek(adr)
print c1*9
does not work. The same if I use such a calculation as Parameter for a sub.
Any chance to fix this?

Another Problem:
Code:
print at 17,0;1<<3+2
Usually bit shifting should have the highest poriority, not the addition, thats why the result is 1<<(3+2)=32, but it should be (1<<3)+2=10.

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