Re: Sv: A83: Re: Re:
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Re: Sv: A83: Re: Re:
bah, linus is just being mean for some reason... what he means is it will
change the value of hl which ret wouldn't do
-Dan
-----Original Message-----
From: Thomas Turn Jensen <Mukke@get2net.dk>
To: assembly-83@lists.ticalc.org <assembly-83@lists.ticalc.org>
Date: Wednesday, September 16, 1998 2:47 PM
Subject: Sv: Sv: A83: Re: Re:
>
>Honestly I don't see what you mean. First, it sure looked like assembler to
me, 2nd why would ret trash hl (and what has that got to do with it?)
>
>(sorry if I've gotten all this wrong... :-)
>
>-----Oprindelig meddelelse-----
>Fra: Linus Akesson <lairfight@softhome.net>
>Til: Thomas Turn Jensen <assembly-83@lists.ticalc.org>
>Dato: 15. september 1998 20:59
>Emne: Re: Sv: A83: Re: Re:
>
>
>>
>>Oh please... That was pseudo code describing the ret instruction. Your
code
>>might compile better, but ret doesn't trash hl, does it?
>>
>>Linus
>>
>>On 15-Sep-98, Thomas Turn Jensen wrote:
>>
>>>Not that it's very important but couldn't you just have this instead of
ret:
>>
>>>lh hl,(sp) ; not possible :(
>>>dec sp
>>>dec sp
>>>ld pc,hl ; not possible
>>
>>>Anyways, loading pc isn't possible according to the Tasm80.tab so this is
>>>quite meaningles.
>>
>>
>>>***
>>>Thomas Turn Jensen
>>>Icq uin => 8128636
>>>IRC, Undernet => Mukke
>>>***
>>>Får computeren dig til at sukke?
>>>Så kald da blot på Mukke
>>>***
>>
>>
>>>-----Oprindelig meddelelse-----
>>>Fra: Alan C Johnson <benjamin99@juno.com>
>>>Til: assembly-83@lists.ticalc.org <assembly-83@lists.ticalc.org>
>>>Dato: 13. september 1998 22:22
>>>Emne: Re: A83: Re: Re:
>>
>>
>>>>
>>>>The stack pointer points to the memory location in the RAM that is used
>>>>for the stack. Now here's a little bit of useless info. By the way,
>>>>does anyone know where thestack memory starts and ends
>>>>
>>>>Basically, if there was no push command, you would have to do this:
>>>>
>>>> inc sp ; 2 because the stack locations are 16-bits
>>>> inc sp
>>>> ld (sp),rr
>>>>
>>>>Pop would be:
>>>> ld rr,(sp)
>>>> dec sp
>>>> dec sp
>>>>
>>>>Call would be:
>>>> inc sp
>>>> inc sp
>>>> ld (sp),pc
>>>> jp xxxx ; jp actually being ld pc,xxxx
>>>>
>>>>Ret would basically be:
>>>> ld pc,(sp) ; which would actually be impossible, because it would jump
>>>>as soon as you
>>>> dec sp ; loaded the pc register, so it wouldn't post-decrement the
>>>>stack pointer
>>>> dec sp
>>>>
>>>>
>>>>>
>>>>>Would someone like to explain the stack pointer in more detail? I
>>>>>know
>>>>>*roughly* what it does...no, actually I don't :)...
>>>>>
>>>>>Later,
>>>>>
>>>>>James Matthews (matthews@tkb.att.ne.jp)
>>>>>
>>>>>ICQ: 7413754
>>>>>http://home.att.ne.jp/gold/tomcat21/index.html
>>>>>http://library.advanced.org/18242/
>>>>>
>>>>>----------
>>>>>> From: Scott Dial (Revenant) <homosapian@geocities.com>
>>>>>> To: assembly-83@lists.ticalc.org
>>>>>> Subject: A83: Re:
>>>>>> Date: Sunday, September 13, 1998 9:28 AM
>>>>>>
>>>>>>
>>>>>> Exactly that...
>>>>>>
>>>>>> sp is a z80 register for the position of stack pointer... so that he
>>>>>can
>>>>>> return to that exact point later. spbak is defined at the bottom:
>>>>>spbak
>>>>>> .dw $0000
>>>>>>
>>>>>> Patrick W Bambrough wrote:
>>>>>> >
>>>>>> > hey can anyone tell me what this means and if there is an 83
>>>>>equivelant??
>>>>>> > ld (spbak),sp
>>>>>>
>>>>>> --
>>>>>> Scott Dial
>>>>>> revenant_1@hotmail.com
>>>>>> ICQ#3608935
>>>>>
>>>>
>>>>_____________________________________________________________________
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>>>>
>>
>>
>>
>>
>