Sender: nate AT cartsys DOT com
Message-ID: <35C8A6FA.33C4E602@cartsys.com>
Date: Wed, 05 Aug 1998 11:39:54 -0700
From: Nate Eldredge <nate AT cartsys DOT com>
MIME-Version: 1.0
To: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
CC: djgpp-workers AT delorie DOT com
Subject: Re: emu387 functions undocumented/undeclared
References: <Pine DOT SUN DOT 3 DOT 91 DOT 980805093803 DOT 11089H-100000 AT is>
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Eli Zaretskii wrote:
> 
> On Tue, 4 Aug 1998, Nate Eldredge wrote:
> 
> > The functions in the emu387 tree of libc aren't documented, and also
> > aren't declared in any headers.  The major one of interest is
> > `_detect_80387'; there is also `_npxsetup' and a few globals.  I will
> > write the docs, but what header should they go in (if any)?
> 
> I suggest <dos.h> for `_detect_80387', since that's where the _8087
> global variable is declared in TC and BC.  And while at that, how
> about adding _8087 as well?

Herewith the patch that accomplishes that.

> > Also, what is the policy on documentation of functions?  libc.inf says
> > it documents "all public symbols", but that's not really the case.  Some
> > public symbols are internal to the library and completely useless to an
> > application.  (Examples: __crt1_startup, and the dummy
> > __emu387_load_hook.)  Should we document them, if only to say "internal
> > to libc, don't use"?
> 
> Personally, I think that everything should be documented.  The reason
> is that, given a good index in libc.info, a user can look up relevant
> functionality in a centralized place.  Without that, the only option
> is to grep the library sources (or use ID-utils) which leave no real
> clues about the purpose of these facilities except what their names
> tell.
> 
> That said, I'm not the one who makes policy decisions around here.
> 
> In practice, I would first worry about documenting *useful*
> functionality, like the `end' symbol, before we get to documenting the
> rest of them.

Good point.  DJ?

-- 

Nate Eldredge
nate AT cartsys DOT com
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*** include/dos.h~	Wed Jun 12 16:56:20 1996
--- include/dos.h	Wed Aug  5 11:29:42 1998
***************
*** 10,15 ****
--- 10,19 ----
  
  #include <pc.h>
  
+ extern int _8087;
+ 
+ int _detect_80387(void);
+ 
  struct DWORDREGS {
    unsigned long edi;
    unsigned long esi;
*** src/libc/emu387/npxsetup.old	Wed Aug  5 11:30:52 1998
--- src/libc/emu387/npxsetup.c	Wed Aug  5 11:31:18 1998
***************
*** 17,22 ****
--- 17,23 ----
  #include <libc/internal.h>
  #include <sys/exceptn.h>
  #include <float.h>
+ #include <dos.h> /* for _8087 */
  #ifndef IMBED_EMU387
  #include <sys/dxe.h>
  static int (*_emu_entry)(jmp_buf exc);
***************
*** 24,29 ****
--- 25,32 ----
  int _emu_entry(jmp_buf exc);
  #endif
  
+ int _8087;
+ 
  /* crt0.o references __emu387_load_hook just to pull in this object in libemu.a.
     Using -lemu -lc brings in the static objects instead of a dynamic link. */
  
***************
*** 74,79 ****
--- 77,83 ----
         nested FPU client fault - DJ */
      __dpmi_set_coprocessor_emulation(1);
      have_80387 = _detect_80387();
+     _8087 = (have_80387 ? 3 : 0);
    }
  
    if (cp && (tolower(cp[0]) == 'q')) {
*** /dev/nul	Wed Aug  5 11:32:11 1998
--- src/libc/emu387/fpu.txh	Wed Aug  5 11:29:40 1998
***************
*** 0 ****
--- 1,42 ----
+ @node _detect_80387, cpu
+ @subheading Syntax
+ 
+ @example
+ #include <dos.h>
+ 
+ int _detect_80387(void);
+ @end example
+ 
+ @subheading Description
+ 
+ Detects whether a numeric coprocessor is present.  Note that
+ floating-point will work even without a coprocessor, due to the
+ existence of emulation.
+ 
+ @subheading Return Value
+ 
+ 1 if a coprocessor is present, 0 if not.
+ 
+ @subheading Example
+ 
+ @example
+ if (_detect_80387())
+   printf("You have a coprocessor\n");
+ @end example
+ 
+ @c ----------------------------------------------------------------------
+ @node _8087, cpu
+ @subheading Syntax
+ 
+ @example
+ #include <dos.h>
+ 
+ extern int _8087;
+ @end example
+ 
+ @subheading Description
+ 
+ Contains @code{3} if a numeric coprocessor is installed, otherwise
+ @code{0}.  Provided for compatibility with other DOS compilers.
+ 
+ @c ----------------------------------------------------------------------

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