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i386.h

Go to the documentation of this file.

/*
 * QuickThreads -- Threads-building toolkit.
 * Copyright (c) 1993 by David Keppel
 *
 * Permission to use, copy, modify and distribute this software and
 * its documentation for any purpose and without fee is hereby
 * granted, provided that the above copyright notice and this notice
 * appear in all copies.  This software is provided as a
 * proof-of-concept and for demonstration purposes; there is no
 * representation about the suitability of this software for any
 * purpose.
 */

#ifndef QUICKTHREADS_386_H
#define QUICKTHREADS_386_H

typedef unsigned long qt_word_t;

/* Thread's initial stack layout on the i386:

   non-varargs:

   +---
   | arg[2] === `userf' on startup
   | arg[1] === `pt' on startup
   | arg[0] === `pu' on startup
   +---
   | ret pc === qt_error
   +---
   | ret pc === `only' on startup
   +---
   | %ebp
   | %esi
   | %edi
   | %ebx       <--- qt_t.sp
   +---

   When a non-varargs thread is started, it ``returns'' directly to
   the client's `only' function.

   varargs:

   +---
   | arg[n-1]
   | ..
   | arg[0]
   +---
   | ret pc === `qt_vstart'
   +---
   | %ebp === `startup'
   | %esi === `cleanup'
   | %edi === `pt'
   | %ebx === `vuserf'    <--- qt_t.sp
   +---

   When a varargs thread is started, it ``returns'' to the `qt_vstart'
   startup code.  The startup code calls the appropriate functions. */


/* What to do to start a varargs thread running. */
extern void qt_vstart (void);


/* Hold 4 saved regs plus two return pcs (qt_error, qt_start) plus
   three args. */
#define QUICKTHREADS_STKBASE  (9 * 4)

/* Hold 4 saved regs plus one return pc (qt_vstart). */
#define QUICKTHREADS_VSTKBASE (5 * 4)


/* Stack must be 4-byte aligned. */
#define QUICKTHREADS_STKALIGN (4)


/* Where to place various arguments. */
#define QUICKTHREADS_ONLY_INDEX (QUICKTHREADS_PC)
#define QUICKTHREADS_USER_INDEX (QUICKTHREADS_ARG2)
#define QUICKTHREADS_ARGT_INDEX (QUICKTHREADS_ARG1)
#define QUICKTHREADS_ARGU_INDEX (QUICKTHREADS_ARG0)

#define QUICKTHREADS_VSTARTUP_INDEX (QUICKTHREADS_EBP)
#define QUICKTHREADS_VUSERF_INDEX   (QUICKTHREADS_EBX)
#define QUICKTHREADS_VCLEANUP_INDEX (QUICKTHREADS_ESI)
#define QUICKTHREADS_VARGT_INDEX    (QUICKTHREADS_EDI)


#define QUICKTHREADS_EBX  0
#define QUICKTHREADS_EDI  1
#define QUICKTHREADS_ESI  2
#define QUICKTHREADS_EBP  3
#define QUICKTHREADS_PC 4
/* The following are defined only for non-varargs. */
#define QUICKTHREADS_RPC  5
#define QUICKTHREADS_ARG0 6
#define QUICKTHREADS_ARG1 7
#define QUICKTHREADS_ARG2 8


/* Stack grows down.  The top of the stack is the first thing to
   pop off (preincrement, postdecrement). */
#define QUICKTHREADS_GROW_DOWN

extern void qt_error (void);

/* Push on the error return address. */
#define QUICKTHREADS_ARGS_MD(sto) \
  (QUICKTHREADS_SPUT (sto, QUICKTHREADS_RPC, qt_error))


/* When varargs are pushed, allocate space for all the args. */
#define QUICKTHREADS_VARGS_MD0(sto, nbytes) \
  ((qt_t *)(((char *)(sto)) - QUICKTHREADS_STKROUNDUP(nbytes)))

#define QUICKTHREADS_VARGS_MD1(sto) \
  (QUICKTHREADS_SPUT (sto, QUICKTHREADS_PC, qt_vstart))

#define QUICKTHREADS_VARGS_DEFAULT

#endif /* QUICKTHREADS_386_H */

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