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+---- Thread: Weirdness 4 (/showthread.php?tid=148)
Weirdness 4 - britlion - 2010-01-31
Okay, this one is pretty small. It crashes.
Code:
FUNCTION RAND () as uInteger : REM Code by Jon Ritman
random: REM add 46 bytes to this location to hit the store "Lion"
asm
RANDOM: LD HL,(SEED+2)
LD D,L
ADD HL,HL
ADD HL,HL
LD C,H
LD HL,(SEED)
LD B,H
RL B
LD E,H
RL E
RL D
ADD HL,BC
LD (SEED),HL
LD HL,(SEED+2)
ADC HL,DE
RES 7,H
LD (SEED+2),HL
JP M,RANDOM3
LD HL,SEED
RANDOM2: INC (HL)
INC HL
JR Z,RANDOM2
RANDOM3: LD HL,(SEED)
RET
SEED: DB "Lion"
end asm
END FUNCTION
CLS
DIM a as uInteger
let a=@random
PRINT a
let a=a+46
PRINT a
DIM n as uInteger
DIM result as uByte
FOR n=a to a+4
LET result=peek n
print n;"=";result;"=";CHR$ (result)
next nIF I change the last line to:
Code:
print n;"=";result;"=";CHR$ (76)It doesn't crash. What's the problem with CHR$(uByte) suddenly?
Can anyone else replicate this?
All I was trying to do was put in a nice shiny new random number generator...
Re: Weirdness 4 - boriel - 2010-02-21
britlion Wrote:Okay, this one is pretty small. It crashes.
Code:FUNCTION RAND () as uInteger : REM Code by Jon Ritman
random: REM add 46 bytes to this location to hit the store "Lion"
asm
RANDOM: LD HL,(SEED+2)
LD D,L
ADD HL,HL
ADD HL,HL
LD C,H
LD HL,(SEED)
LD B,H
RL B
LD E,H
RL E
RL D
ADD HL,BC
LD (SEED),HL
LD HL,(SEED+2)
ADC HL,DE
RES 7,H
LD (SEED+2),HL
JP M,RANDOM3
LD HL,SEED
RANDOM2: INC (HL)
INC HL
JR Z,RANDOM2
RANDOM3: LD HL,(SEED)
RET
SEED: DB "Lion"
end asm
END FUNCTION
CLS
DIM a as uInteger
let a=@random
PRINT a
let a=a+46
PRINT a
DIM n as uInteger
DIM result as uByte
FOR n=a to a+4
LET result=peek n
print n;"=";result;"=";CHR$ (result)
next n
IF I change the last line to:
Code:print n;"=";result;"=";CHR$ (76)
It doesn't crash. What's the problem with CHR$(uByte) suddenly?
Can anyone else replicate this?
All I was trying to do was put in a nice shiny new random number generator...
This program does not crash to me. Try it with the new 1.2.5 Beta 2 version, anyway. It prints Lion# where # means rubbish.
The problem here is you're printing 5 chars (a, a+1, a+2, a+3, a+4) and Lion has 4 letters. You have an overflow in your print, so the glitched character is expected. But the program should not crash (It does not in my emulator).
Can you try with V 1.2.5 Beta 2?