From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Thu, 10 Mar 2005 14:55:37 -0700
From: "Ronald G. Minnich" <rminnich@lanl.gov>
To: 9fans@cse.psu.edu
Message-ID: <Pine.LNX.4.58.0503101453470.13080@enigma.lanl.gov>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Subject: [9fans] ARM question
Topicbox-Message-UUID: 227884b2-ead0-11e9-9d60-3106f5b1d025


here's the code in c:
#include <u.h>
#include <libc.h>
y(){
	unsigned long *x;
	x = (unsigned long *) 0x4000;
	*x = (unsigned long) 0x40e;
}
main(){
	unsigned long *x;
	static unsigned long y[64];
	int i;

	x = (unsigned long *) 0x4000;
	*x = (unsigned long) 0x40e;
	x++;
	*x = (unsigned long)0x100000 + 0x40e;
	x++;
	*x = (unsigned long)0x200000 + 0x40e;
	x++;
	*x = (unsigned long)0x300000 + 0x40e;
	x++;
	*x = (unsigned long)0x400000 + 0x40e;
	x++;
	*x = (unsigned long)0x500000 + 0x40e;
	x++;
	*x = (unsigned long)0x600000 + 0x40e;
	x++;
	*x = (unsigned long)0x700000 + 0x40e;

}

And the .s
	TEXT	y+0(SB),0,$4
	MOVW	$1038,R4
	MOVW	$16384,R1
	MOVW	R4,0(R1)
	RET	,
	TEXT	main+0(SB),0,$8
	MOVW	$1049614,R10
	MOVW	$2098190,R9
	MOVW	$3146766,R8
	MOVW	$4195342,R7
	MOVW	$5243918,R6
	MOVW	$6292494,R5
	MOVW	$7341070,R4
	MOVW	$16384,R3
	MOVW	$1038,R2
	MOVW.P	R2,4(R3)
	MOVW.P	R10,4(R3)
	MOVW.P	R9,4(R3)
	MOVW.P	R8,4(R3)
	MOVW.P	R7,4(R3)
	MOVW.P	R6,4(R3)
	MOVW	R5,0(R3)
	MOVW	R4,4(R3)
	RET	,
	GLOBL	y$2<>+0(SB),R0,$256
	END	,

The code for y() I can understand.

but this:

	MOVW	$16384,R3
	MOVW	$1038,R2
	MOVW.P	R2,4(R3)

I don't get. How can R2 get stored to 16384, given the 4(R3)?

Are we pretty much agreed that the MOVW.P is a post-increment mode?

ron