Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.forth > #26550

Re: A problem with gforth-fast

Show all headers | View raw

anton@mips.complang.tuwien.ac.at (Anton Ertl) writes:
>And given that spTOS is not clobbered by calls in general, but only by
>a few transcendental functions, it seems that gcc mostly gets this
>right.  But not always.  I'll look into that later.

Ok, now I did.  I started with the current git, and I had to disable
two workarounds: The new TOS_CLOBBERED flag and the older one (in
test/float.fs) that tests whether certain FP words clobber the TOS
(and then explicit registers are disabled automatically).

With gcc-4.6.3 I indeed get TOS in ecx:

see 1+ 
Code 1+  
( $804BC6A )  add     ebx , # 4  \ $83 $C3 $4 
( $804BC6D )  inc     ecx  \ $41 
( $804BC6E )  mov     ebp , dword ptr FC [ebx]  \ $8B $6B $FC 
( $804BC71 )  mov     eax , ebp  \ $89 $E8 
( $804BC73 )  jmp     eax  \ $FF $E0 
end-code

and FCOS indeed does not save ecx when calling cos():

see fcos 
Code fcos  
( $804DFEF )  mov     ebp , dword ptr 50 [esp]  \ $8B $6C $24 $50 
( $804DFF3 )  add     ebx , # 4  \ $83 $C3 $4 
( $804DFF6 )  fld     double dword ptr 0 [ebp]  \ $DD $45 $0 
( $804DFF9 )  fstp    double dword ptr [esp]  \ $DD $1C $24 
( $804DFFC )  call    804AA10  \ $E8 $F $CA $FF $FF 
( $804E001 )  fstp    double dword ptr 0 [ebp]  \ $DD $5D $0 
( $804E004 )  mov     ebp , dword ptr FC [ebx]  \ $8B $6B $FC 
( $804E007 )  mov     eax , ebp  \ $89 $E8 
( $804E009 )  jmp     eax  \ $FF $E0 
end-code

Yet the test case at the start of the thread does not clobber TOS on
my system, but FCOSH does clobber it, and the code for it looks
very similar:

see fcosh 
Code fcosh  
( $804E17F )  mov     ebp , dword ptr 50 [esp]  \ $8B $6C $24 $50 
( $804E183 )  add     ebx , # 4  \ $83 $C3 $4 
( $804E186 )  fld     double dword ptr 0 [ebp]  \ $DD $45 $0 
( $804E189 )  fstp    double dword ptr [esp]  \ $DD $1C $24 
( $804E18C )  call    804AF60  \ $E8 $CF $CD $FF $FF 
( $804E191 )  fstp    double dword ptr 0 [ebp]  \ $DD $5D $0 
( $804E194 )  mov     ebp , dword ptr FC [ebx]  \ $8B $6B $FC 
( $804E197 )  mov     eax , ebp  \ $89 $E8 
( $804E199 )  jmp     eax  \ $FF $E0 
end-code

12345 0e fcosh cr f. . 
1. -1073741825  ok

- anton
-- 
M. Anton Ertl  http://www.complang.tuwien.ac.at/anton/home.html
comp.lang.forth FAQs: http://www.complang.tuwien.ac.at/forth/faq/toc.html
     New standard: http://www.forth200x.org/forth200x.html
   EuroForth 2013: http://www.euroforth.org/ef13/

Back to comp.lang.forth | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

A problem with gforth-fast humptydumpty <ouatubi@gmail.com> - 2013-10-11 02:51 -0700
  Re: A problem with gforth-fast Bernd Paysan <bernd.paysan@gmx.de> - 2013-10-11 17:00 +0200
    Re: A problem with gforth-fast humptydumpty <ouatubi@gmail.com> - 2013-10-11 08:54 -0700
    Re: A problem with gforth-fast Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-10-11 10:57 -0500
      Re: A problem with gforth-fast Bernd Paysan <bernd.paysan@gmx.de> - 2013-10-11 18:49 +0200
        Re: A problem with gforth-fast Bernd Paysan <bernd.paysan@gmx.de> - 2013-10-11 21:08 +0200
          Re: A problem with gforth-fast humptydumpty <ouatubi@gmail.com> - 2013-10-11 12:54 -0700
            Re: A problem with gforth-fast Bernd Paysan <bernd.paysan@gmx.de> - 2013-10-11 23:21 +0200
              Re: A problem with gforth-fast humptydumpty <ouatubi@gmail.com> - 2013-10-11 23:58 -0700
        Re: A problem with gforth-fast Bernd Paysan <bernd.paysan@gmx.de> - 2013-10-11 21:30 +0200
        Re: A problem with gforth-fast Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-10-12 03:06 -0500
          Re: A problem with gforth-fast Bernd Paysan <bernd.paysan@gmx.de> - 2013-10-12 15:50 +0200
          Re: A problem with gforth-fast anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-10-14 17:17 +0000
            Re: A problem with gforth-fast Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-10-14 12:49 -0500
              Re: A problem with gforth-fast anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-10-15 09:50 +0000
                Re: A problem with gforth-fast Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-10-15 07:48 -0500
                Re: A problem with gforth-fast anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-10-15 13:35 +0000
                Re: A problem with gforth-fast Bernd Paysan <bernd.paysan@gmx.de> - 2013-10-15 17:09 +0200
                Re: A problem with gforth-fast anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-10-16 16:36 +0000

csiph-web