Re: 6502 stack register at reset

From: silverdr_at_wfmh.org.pl Date: Sat, 25 Nov 2017 21:34:33 +0100 Message-Id: <02732266-553B-4E8A-B198-215AE80659CC@wfmh.org.pl>

> On 2017-11-25, at 20:59, Gerrit Heitsch <gerrit@laosinh.s.bawue.de> wrote:
> 
> On 11/25/2017 08:50 PM, didier derny wrote:
>> Is there any 6502 starting with an initialized stack register at reset ?
>> a few month ago I was struggling with a strange bug...
>> the program was crashing or working randomly
>> I discovered that the machine had a stack register never initialized
> 
> As far as I know, the RESET squence on about every 6502 system contains the following 2 commands:
> 
> LDX #$FF
> TXS
> 
> to make sure the stack pointer contains the proper value.

Yup - I even remember wondering why.. long time ago. That's until I read somewhere that the SP is not initialised on H/W reset.

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