Re: When to use !name vs. name! ?

From	Alex <alex@rivadpm.com>
Newsgroups	comp.lang.forth
Subject	Re: When to use !name vs. name! ?
Date	2017-03-19 17:42 +0000
Organization	A noiseless patient Spider
Message-ID	<oamfnv$rrb$1@dont-email.me> (permalink)
References	(7 earlier) <oakpjr$lf6$1@dont-email.me> <bJmdndkW2_YCc1DFnZ2dnUU7-U_NnZ2d@supernews.com> <oakv5o$qc1$2@dont-email.me> <L_6dnTsdnMh9olPFnZ2dnUU7-QXNnZ2d@supernews.com> <2017Mar19.170308@mips.complang.tuwien.ac.at>

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On 3/19/2017 16:03, Anton Ertl wrote:
> "Elizabeth D. Rather" <erather@forth.com> writes:

>
>> In most ITC Forths, the stack pointer is in a register, and an increment
>> or shift is one instruction (possibly indirect). There is no read or
>> write. I don't remember any instruction sets in which it is not possible
>> to increment or shift left the TOS in one instruction. A C
>> implementation, of course, may be much less efficient.
>
> Just to illustrate this, here's what you get in gforth-fast:
>
> : foo 1+ 2* ;  ok
> : bar 1 + 2 * ;  ok
> see-code foo
> $7F2CA4B88390 1+
> 7F2CA4AF6505:   add     rbx,$08   \ update ip (of threaded code)
> 7F2CA4AF6509:   add     r14,$01   \ tos = tos + 1
> $7F2CA4B88398 2*
> 7F2CA4AF650D:   add     rbx,$08   \ update ip (of threaded code)
> 7F2CA4AF6511:   add     r14,r14   \ tos = tos + tos
> $7F2CA4B883A0 ;s
> see-code bar
> $7F2CA4B883E0 lit
> $7F2CA4B883E8 <$1>
> $7F2CA4B883F0 <$0>                \ actually +, but combined with LIT
> 7F2CA4AF6529:   add     r14,[rbx] \ tos = tos + *ip
> 7F2CA4AF652C:   add     rbx,$18   \ update ip (of threaded code)
> $7F2CA4B883F8 noop                \ actually LIT, decompiler acting up
> $7F2CA4B88400 <$2>
> 7F2CA4AF6530:   mov     [r15],r14
> 7F2CA4AF6533:   sub     r15,$08
> 7F2CA4AF6537:   mov     rax,rbx
> 7F2CA4AF653A:   lea     rbx,$10[rbx]
> 7F2CA4AF653E:   mov     r14,[rax]
> $7F2CA4B88408 *
> 7F2CA4AF6541:   mov     rax,r15
> 7F2CA4AF6544:   lea     r15,$08[r15]
> 7F2CA4AF6548:   add     rbx,$08
> 7F2CA4AF654C:   imul    r14,$08[rax]
> $7F2CA4B88410 ;s ok
>
> In the BAR example you see that Gforth-fast has a static
> superinstruction for "lit <num> +", but none for "lit <num> *".  So
> for the "2 *" you see all the stack access overhead.  You don't see
> threaded-code overhead apart from the ip updates thanks to dynamic
> superinstructions.  And it looks like we are now using Intel assembler
> syntax in the disassembler.

STC Experimental 32bit: 0.06.08 Build: 781
: foo 1+ 2* ;  ok
: bar 1 + 2 * ;  ok
see foo
: foo ( ? -- ? )
\ foo is defined in (console)
\ call compiled
\ code=$41C550 len=5 type=130
( $0 )    add     eax $1                            \ 83C001
( $3 )    add     eax eax                           \ 03C0
( $5 )    ret                                       \ C3 ( end ) ok
see bar
: bar ( ? -- ? )
\ bar is defined in (console)
\ call compiled
\ code=$41C55B len=5 type=130
( $0 )    add     eax $1                            \ 83C001
( $3 )    add     eax eax                           \ 03C0
( $5 )    ret                                       \ C3 ( end ) ok

I'm still working on a full optimizer (using SSA) but this one is not 
hard to optimize.

-- 
Alex

Thread

When to use  !name  vs.  name! ? "HAA" <someone@microsoft.com> - 2017-03-14 11:15 +1100
  Re: When to use  !name  vs.  name! ? hughaguilar96@gmail.com - 2017-03-13 18:27 -0700
    Re: When to use  !name  vs.  name! ? Mark Wills <markwills1970@gmail.com> - 2017-03-14 01:33 -0700
  Re: When to use  !name  vs.  name! ? Mark Wills <markwills1970@gmail.com> - 2017-03-14 01:30 -0700
  When to use  !name  vs.  name! ? NN <november.nihal@gmail.com> - 2017-03-14 02:56 -0700
    Re: When to use  !name  vs.  name! ? "HAA" <someone@microsoft.com> - 2017-03-16 08:59 +1100
      Re: When to use  !name  vs.  name! ? Mark Wills <markwills1970@gmail.com> - 2017-03-16 02:11 -0700
        Re: When to use  !name  vs.  name! ? "HAA" <someone@microsoft.com> - 2017-03-17 11:19 +1100
  Re: When to use !name vs. name! ? rickman <gnuarm@gmail.com> - 2017-03-16 20:46 -0400
    Re: When to use !name vs. name! ? "Elizabeth D. Rather" <erather@forth.com> - 2017-03-16 21:34 -1000
      Re: When to use !name vs. name! ? "HAA" <someone@microsoft.com> - 2017-03-18 09:49 +1100
        Re: When to use !name vs. name! ? "Elizabeth D. Rather" <erather@forth.com> - 2017-03-17 13:08 -1000
          Re: When to use !name vs. name! ? rickman <gnuarm@gmail.com> - 2017-03-17 19:35 -0400
            Re: When to use !name vs. name! ? Mark Wills <markwills1970@gmail.com> - 2017-03-18 00:51 -0700
            Re: When to use !name vs. name! ? "HAA" <someone@microsoft.com> - 2017-03-19 10:47 +1100
              Re: When to use !name vs. name! ? rickman <gnuarm@gmail.com> - 2017-03-18 22:18 -0400
                Re: When to use !name vs. name! ? "Elizabeth D. Rather" <erather@forth.com> - 2017-03-18 16:36 -1000
                Re: When to use !name vs. name! ? rickman <gnuarm@gmail.com> - 2017-03-18 23:53 -0400
                Re: When to use !name vs. name! ? "Elizabeth D. Rather" <erather@forth.com> - 2017-03-18 22:22 -1000
                Re: When to use !name vs. name! ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-03-19 16:03 +0000
                Re: When to use !name vs. name! ? Alex <alex@rivadpm.com> - 2017-03-19 17:42 +0000
                Re: When to use !name vs. name! ? "Elizabeth D. Rather" <erather@forth.com> - 2017-03-19 13:10 -1000
                Re: When to use !name vs. name! ? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-03-19 13:34 +0100
                Re: When to use !name vs. name! ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-03-19 16:23 +0000
                Re: When to use !name vs. name! ? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-03-19 20:47 +0100
                Re: When to use !name vs. name! ? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-03-20 03:47 -0500
                Re: When to use !name vs. name! ? "HAA" <someone@microsoft.com> - 2017-03-20 09:41 +1100
                Re: When to use !name vs. name! ? Coos Haak <htrofhc@gmail.com> - 2017-03-20 01:24 +0100
                Re: When to use !name vs. name! ? "HAA" <someone@microsoft.com> - 2017-03-21 12:10 +1100
                Re: When to use !name vs. name! ? hughaguilar96@gmail.com - 2017-03-20 18:45 -0700
                Re: When to use !name vs. name! ? Coos Haak <htrofhc@gmail.com> - 2017-03-21 14:58 +0100
                Re: When to use !name vs. name! ? "HAA" <someone@microsoft.com> - 2017-03-22 19:49 +1100
          Re: When to use !name vs. name! ? hughaguilar96@gmail.com - 2017-03-17 16:46 -0700
  Re: When to use  !name  vs.  name! ? Lars Brinkhoff <lars.spam@nocrew.org> - 2017-04-12 08:13 +0200

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