[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Branches in AMD64 assembler

From: anthony
Subject: Re: Branches in AMD64 assembler
Date: Mon, 17 Aug 2020 10:56:48 +0100
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0

On 16/08/2020 15:28, David Kuehling wrote:
"anthony" == anthony  <> writes:
Hello, after reading the gforth manual, the list archive and the
comp.lang.forth newsgroup I was unable to find any documentation or an
example with a loop in ASM64 and ABI-CODE.  I expected something like
ABI-CODE TEST    0 # R10 MOV L1:   1 # R10 ADD   10 # R10 CMP    L1
I think, you most of Gforth's assemblers supply forth-like control flow
words, to compile branches, using the stack to resolve forward/backwards
branch references (no labels), i.e. write something like

       10 # R10 CMP

Looking at amd64/asm.fs, I see that condition-codes are supported in
"assembler" as well as "operator" syntax:

   $10 cond: vs vc   u< u>=  0= 0<>  u<= u>   0< 0>=  ps pc   <  >=   <=  >
   $10 cond: o  no   b  nb   z  nz   be  nbe  s  ns   pe po   l  nl   le  nle

I.e. you could write '<= UNTIL'  as well as 'LE UNTIL'

See also Gforth's manual or the amd64/asm.fs implementation:



Hi David,

thanks for your reply, this was exactly the hint I needed to go further.
I will post a number of examples in a separate post for others with a similar question in the future.

Cheers, Anthony

reply via email to

[Prev in Thread] Current Thread [Next in Thread]