start.s

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/************************************************************************
 *
 *  start.S
 *
 *  Startup code for application.
 *
 * ######################################################################
 *
 * mips_start_of_legal_notice
 * 
 * Copyright (c) 2002 MIPS Technologies, Inc. All rights reserved.
 *
 *
 * Unpublished rights (if any) reserved under the Copyright Laws of the
 * United States of America.
 *
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 * such as in FrameMaker or Microsoft Word format), then its use and
 * distribution is subject to a written agreement with MIPS Technologies,
 * Inc. ("MIPS Technologies"). UNDER NO CIRCUMSTANCES MAY A DOCUMENT
 * PROVIDED IN SOURCE FORMAT BE DISTRIBUTED TO A THIRD PARTY WITHOUT THE
 * EXPRESS WRITTEN CONSENT OF MIPS TECHNOLOGIES.
 *
 * This document contains information that is proprietary to MIPS
 * Technologies. Any copying, reproducing, modifying, or use of this
 * information (in whole or in part) which is not expressly permitted in
 * writing by MIPS Technologies or a contractually-authorized third party is
 * strictly prohibited. At a minimum, this information is protected under
 * unfair competition and copyright laws. Violations thereof may result in
 * criminal penalties and fines.
 *
 * MIPS Technologies or any contractually-authorized third party reserves
 * the right to change the information contained in this document to improve
 * function, design or otherwise. MIPS Technologies does not assume any
 * liability arising out of the application or use of this information, or
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 * mips_end_of_legal_notice
 * 
 *
 ************************************************************************/

/************************************************************************
 *  Include files
 ************************************************************************/

#include <regdefs.h>
	
/************************************************************************
 *  Definitions
 ************************************************************************/

/************************************************************************
 *  Public variables
 ************************************************************************/

/************************************************************************
 *  Static variables
 ************************************************************************/

/************************************************************************
 *  Implementation : Static functions
 ************************************************************************/
	
/************************************************************************
 *  Implementation : Public functions
 ************************************************************************/


      .text


/************************************************************************
 *
 *                          _start
 *  Description :
 *  -------------
 *
 *  Function linked to application start address
 *
 *  Initialises sp and gp registers and clears bss section
 *
 *  Return values :
 *  ---------------
 *
 *  None
 *
 ************************************************************************/
	
      .globl _start
      .ent   _start
	
_start:	

      .set noreorder

#ifdef __ghs__
      /* Setup sp and gp */
      la    gp, __ghsbegin_sdabase
      addiu gp, gp, 0x4000
      addiu gp, gp, 0x4000
      la    sp, __ghsend_stack

      /* Clear bss */
      la    t0, __ghsbegin_sbss
      la    t1, __ghsend_bss
#else
      /* Setup sp and gp */
      la    gp, _gp
      la    sp, _sp

      /* Clear bss */

      la    t0, _fbss	/* First address */
      la    t1, _end	/* Last  address */
#endif
      addu  t1, 3
      li    t2, ~3
      and   t1, t2

1:
      sw    zero, 0(t0)
      bne   t0, t1, 1b
      addiu t0, 4

      /* Get ready to jump to main */
      move  s0, ra
      la    t0, main
      /* Jump to main */
      jal   t0
      nop

      /* Return to monitor */
      jr    s0
      nop	

      .set reorder

      .end   _start




/************************************************************************
 *
 *                          __main, _gccmain
 *  Description :
 *  -------------
 *
 *  Dummy functions called by main() function.
 *
 *  GNU-gcc 2.8.1 : main() calls __main
 *  GNU-gcc 2.9   : main() calls __gccmain
 *	
 *  Return values :
 *  ---------------
 *
 *  None
 *
 ************************************************************************/

      .set noreorder
		
      .globl __main
      .globl __gccmain
      .ent   __main

__main:	
__gccmain:
      jr	ra
      nop

      .end   __main


	
/************************************************************************
 *
 *                          my_add
 *
 *  void my_add(float *result, float *x, float *y);
 *
 *  This routine is placed in assembler to avoid the builtin
 *  fpu emulator of c compilers.
 *
 ************************************************************************/

      .globl my_add
      .ent   my_add
      .set noreorder
	
my_add:	

 	lwc1	$f10, 0(a1)
 	lwc1	$f8, 0(a2)
	add.s	$f10, $f10, $f8
 	jr	ra
 	swc1	$f10,0(a0)

      .set reorder
      .end   my_add



/************************************************************************
 *
 *                          my_dadd
 *
 *  void my_dadd(float *result, float *x, float *y);
 *
 ************************************************************************/

      .globl my_dadd
      .ent   my_dadd
      .set noreorder
	
my_dadd:	

 	lwc1	$f6, 0(a1)
 	lwc1	$f8, 0(a2)

	/* convert to double precision and add */
	cvt.d.s $f0, $f6
	cvt.d.s	$f2, $f8
	add.d	$f4, $f2, $f0

	/* move something into f5 */
	/* if fr=OFF, this will destroy high part of double result in f4,f5 */
	/* if fr=ON,  the result in f4 is unaffected: */
	li	v0, 0x40f00000    /* 7.5000000 */
	mtc1	v0, $f5

	/* convert back to single precision */
	cvt.s.d	$f8, $f4
 	jr	ra
 	swc1	$f8,0(a0)

      .set reorder
      .end   my_dadd