Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!utgpu!water!watmath!clyde!rutgers!gatech!amdcad!tim
From: tim@amdcad.UUCP
Newsgroups: comp.lang.c
Subject: Re: static variables [really segments]
Message-ID: <17000@amdcad.AMD.COM>
Date: Thu, 4-Jun-87 14:05:46 EDT
Article-I.D.: amdcad.17000
Posted: Thu Jun  4 14:05:46 1987
Date-Received: Sat, 6-Jun-87 08:31:00 EDT
References: <7653@brl-adm.ARPA> <196@peaks.UUCP>
Reply-To: tim@amdcad.UUCP (Tim Olson)
Organization: Advanced Micro Devices, Inc., Sunnyvale, Ca.
Lines: 52
Keywords: data1

In article <196@peaks.UUCP> bdw@peaks.UUCP (bruce welker) writes:
>	Where "some string" actually is is up to the compiler writer. The
>	two places I can think of off-hand are:
>		- in the code
>		- in some hidden global data area
>	Would some one who's written a C compiler comment on this?
>
>		Bruce Welker
>		...!hao!boulder!peaks!bdw


This is what the "data 1" segment is for on PCC compilers. Normal
initialized statics are stored in the "data" segment, while strings are
placed in data 1 or data 2, depending upon the type of initialization. 
This allows the compiler to switch back-and-forth between segments to
generate strings in the middle of generating another structure:

-------------------------
char *strings[] = {
	"this",
	"is",
	"a test"
};

-------------------------
LL0:
	.data
	.data				; use the default data segment
	.align	2
	.globl	_strings		; create a global label
_strings:
	.data	2			; switch to the "data 2" segment
L12:					; generate a local (hidden) label
	.ascii	"this\0"		; generate the string
	.data				; switch back to the default segment
	.long	L12			; generate a pointer to the string
	.data	2
L13:
	.ascii	"is\0"
	.data
	.long	L13
	.data	2
L14:
	.ascii	"a test\0"
	.data
	.long	L14
	.data


	-- Tim Olson
	Advanced Micro Devices
	..ihnp4!amdcad!tim