/* --- Copyright University of Sussex 1999. All rights reserved. ----------
 > File:		S.pcunix/src/syscomp/sysdefs_linux_elf.p
 > Purpose:		Definitions for machine & operating system (PC/Linux ELF)
 > Author:		Robert Duncan, Oct 31 1988 (see revisions)
 */


section;

global constant macro (

	POPC_SYSDEFS_LOADED = true,


;;; === SYSTEM NAME (PC) ==============================================


	MACHINE = [[pc]],

	PC = true,
	X86_LINUX = true,


;;; === PROCESSOR (INTEL 80x86) =======================================


	PROCESSOR = [[80386]],		;;; or similar

	;;; Values for machine and C data types are defined in mcdata.p,
	;;; and can be overidden here if necessary

	SHORT_ALIGN_BITS = 8,		;;; alignment in bits for short access
	INT_ALIGN_BITS	 = 8,		;;; alignment in bits for int access
	DOUBLE_ALIGN_BITS = 8,		;;; alignment in bits for double access

	STRUCT_SHORT_ALIGN_BITS	= 16,	;;; bit alignment for short
	STRUCT_INT_ALIGN_BITS   = 32,	;;; bit alignment for int
	STRUCT_DOUBLE_ALIGN_BITS = 32,	;;; bit alignment for double

	CODE_POINTER_TYPE = "byte",	;;; type of pointer to machine code
	BIT_POINTER_TYPE = "byte",	;;; type of pointer for bitfield access


;;; === OPERATING SYSTEM (UNIX BSD) ==================================


	UNIX = true,
	BERKELEY = 4.3,
	LINUX = 2.0,
	LINUX_ELF = true,
	POSIX1 = 198808,			;;; probably later than this ...
	OPERATING_SYSTEM = [[unix linux ^LINUX elf posix {^POSIX1}]],

	SHARED_LIBRARIES = true,

	VPAGE_OFFS = 4096,		;;; word address offset of a virtual page

	;;; LOWEST_ADDRESS:
	LOWEST_ADDRESS = 0,

	;;; UNIX_USRSTACK:
	;;; 	????

	UNIX_USRSTACK  = 16:FC000000,

	;;; Procedures to get and set the memory break and return the REAL end of
	;;; memory. (We always need the real end to ensure that the end of the
	;;; user stack is always at the true end of memory, so that user stack
	;;; underflow produces a memory access violation.)

	GET_REAL_BREAK =
		[procedure(); _extern sbrk(_0)@(b.r->vpage) endprocedure],

	SET_REAL_BREAK =
		[procedure(_break) -> _break;
			lvars _break = _break@(w.r->vpage);
			if _extern brk(_break@(w->b)) == _-1 then
				_-1 -> _break
			endif
		endprocedure],


;;; === OTHER =========================================================

	;;; ANSI C returns floats as single, not double
	ANSI_C = true,
	C_FLOAT_RESULT_SINGLE = true,

	;;; list of procedures to be optimised as subroutine calls
	;;; format of entries is
	;;;		[<pdr name> <nargs> <nresults> <subroutine name>]

	SUBROUTINE_OPTIMISE_LIST =
		[[
			[prolog_newvar	0 1 _prolog_newvar]
			[datakey		1 1 _datakey]
			[prolog_deref	1 1 _prolog_deref]
			[conspair		2 1 _conspair]
		]],

	;;; Old-style I_PUSH/POP_FIELD(_ADDR) instructions in ass.p
	OLD_FIELD_INSTRUCTIONS = true,

	;;; Include M-code listing in assembly language files

	M_DEBUG = false,

);

endsection;		/* $- */



/* --- Revision History ---------------------------------------------------
--- John Gibson, Apr  9 1999
		Changed LINUX to 2.0
--- John Gibson, Jan 21 1999
		Added X86_LINUX
--- Robert Duncan, May 12 1997
		Added OLD_FIELD_INSTRUCTIONS. Removed is* procedures from
		SUBROUTINE_OPTIMISE_LIST (no longer required).
--- Robert Duncan, Apr 25 1996
		New for Linux ELF
--- Integral Solutions Ltd, May 12 1995
		No longer sets TERMINFO for Linux.
--- John Gibson, Mar 21 1995
		Standard machine data type definitions are now in mcdata.p
--- John Gibson, Feb 28 1995
		Added POSIX1 and "posix" entry in OPERATING_SYSTEM, removed H*ERTZ
--- Poplog System, Jan 18 1995 (Julian Clinton)
		Now defaulted to Linux (Berkley-ish with some SVR4).
--- Robert John Duncan, Jan 26 1994
		Modified from Sun386 (now defunct) for PC running SVR4
		(some things left unchecked for now ...)
--- John Gibson, Oct 22 1992
		Changed P*OPC to POPC_SYSDEFS_LOADED
--- Robert John Duncan, Jun 23 1992
		Added BSD_VFORK
--- John Gibson, Dec 11 1990
		SUNOS 4.1
--- Rob Duncan, Aug 31 1989
		Put in value for UNIX_USRSTACK
--- John Gibson, Aug 31 1989
		Added comment for UNIX_USRSTACK, but have no way of finding value.
--- John Gibson, Aug 24 1989
		Removed S+IGNALS
--- Rob Duncan, Apr  3 1989
		Changed OPERATING_SYSTEM definition to include "unix" as well as
		"sunos"
 */