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From: charney@cs.cornell.edu (Mark Charney)
Newsgroups: comp.sys.mips
Subject: double -> int
Message-ID: <1991Jun12.172740.22629@cs.cornell.edu>
Date: 12 Jun 91 17:27:40 GMT
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Organization: Cornell Univ. CS Dept, Ithaca NY 14853
Lines: 79
Originator: charney@turing4.cs.cornell.edu
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Can someone give me the documentation for trunc.w.d?

I'm trying to figure out what is going on with DOUBLE->INT conversion
on my mips chip.  I've included a C program, the associated assembly 
language file and a dissassembly. 


Thanks,
Mark Charney
charney@cs.cornell.edu


---------------------------------------------------------
main()
{
  double a=5;
  int c;
  c = (int) a ;
}

---------------------------------------------------------
	.verstamp	2 10
	.text	
	.align	2
	.file	2 "con.c"
	.globl	main
	.loc	2 2
 #   1	main()
 #   2	{
	.ent	main 2
main:
	.option	O1
	subu	$sp, 16
	.frame	$sp, 16, $31
	.loc	2 3
 #   3	  double a=5;
	li.d	$f4, 5.0000000000000000e+00
	s.d	$f4, 8($sp)
	.loc	2 5
 #   4	  int c;
 #   5	  c = (int) a ;
	trunc.w.d	$f6, $f4, $14
	swc1	$f6, 4($sp)
	.loc	2 6
 #   6	}
	move	$2, $0
	addu	$sp, 16
	j	$31
	.end	main
---------------------------------------------------------



---------------------------------------------------------
(I think the meaning of lines starting with "x" is clear. 
The others seem to be associated with trunc.w.d.)

	MAIN:
  [con.c:   5] 0x4001b0:	444ef800	cfc1	t6,$31
  [con.c:   5] 0x4001b4:	444ef800	cfc1	t6,$31
x [con.c:   3] 0x4001b8:	c7848010	lwc1	$f4,-32752(gp)
x [con.c:   3] 0x4001bc:	c7858014	lwc1	$f5,-32748(gp)

  [con.c:   5] 0x4001c0:	35c10003	ori	at,t6,0x3
  [con.c:   5] 0x4001c4:	38210002	xori	at,at,0x2
  [con.c:   5] 0x4001c8:	44c1f800	ctc1	at,$31
x [con.c:   2] 0x4001cc:	27bdfff0	addiu	sp,sp,-16
  [con.c:   5] 0x4001d0:	462021a4	cvt.w.d	$f6,$f4
x [con.c:   3] 0x4001d4:	e7a40008	swc1	$f4,8(sp)
x [con.c:   5] 0x4001d8:	e7a60004	swc1	$f6,4(sp)
  [con.c:   5] 0x4001dc:	44cef800	ctc1	t6,$31
x [con.c:   3] 0x4001e0:	e7a5000c	swc1	$f5,12(sp)

x [con.c:   6] 0x4001e4:	27bd0010	addiu	sp,sp,16
x [con.c:   6] 0x4001e8:	03e00008	jr	ra
x [con.c:   6] 0x4001ec:	00001021	move	v0,zero

---------------------------------------------------------