Patch to main() invocation in mips/crt0.S

[Richard Sandiford <rsandifo at redhat dot com>]

This patch makes mips/crt0.S call main() with the equivalent of:

        char *argv[1] = { 0 };
        char *envp[1] = { 0 };
        main (0, argv, envp);

Tested 6 ABIs (o32, o64, EABI32, EABI32/long64, EABI64, EABI64/long32)
with a mips64vrel-elf build.  OK to install?

Richard


	* mips/crt0.S (_start): Allocate 64 bytes of stack instead of 32.
	Pass an empty argv and envp to main().

Index: libgloss/mips/crt0.S
===================================================================
RCS file: /cvs/src/src/libgloss/mips/crt0.S,v
retrieving revision 1.5
diff -c -d -p -F^[(a-zA-Z0-9_^#] -r1.5 crt0.S
*** libgloss/mips/crt0.S	12 Nov 2002 23:14:24 -0000	1.5
--- libgloss/mips/crt0.S	17 Dec 2002 10:46:50 -0000
*************** 3:
*** 157,172 ****
  	lw	t0,0(a0)			# last address of memory available
  	la	t1,K0BASE			# cached kernel memory
  	addu	t0,t0,t1			# get the end of memory address
! 	/* We must subtract 24 bytes for the 3 8 byte arguments to main, in
! 	   case main wants to write them back to the stack.  The caller is
! 	   supposed to allocate stack space for parameters in registers in
! 	   the old MIPS ABIs.  We must do this even though we aren't passing
! 	   arguments, because main might be declared to have them.
! 
! 	   Some ports need a larger alignment for the stack, so we subtract
! 	   32, which satisifes the stack for the arguments and keeps the
! 	   stack pointer better aligned.  */
! 	subu	t0,t0,32			# and generate a starting stack-pointer
  4:
  	move	sp,t0				# set stack pointer
  	sw	sp,__stackbase			# keep this for future ref
--- 157,166 ----
  	lw	t0,0(a0)			# last address of memory available
  	la	t1,K0BASE			# cached kernel memory
  	addu	t0,t0,t1			# get the end of memory address
! 	/* Allocate 32 bytes for the register parameters.  Allocate 16
! 	   bytes for a null argv and envp.  Round the result up to 64
! 	   bytes to preserve alignment.  */
! 	subu	t0,t0,64
  4:
  	move	sp,t0				# set stack pointer
  	sw	sp,__stackbase			# keep this for future ref
*************** #endif
*** 213,221 ****
  	jal	_init				# run global constructors
  	nop
  
! 	move	a0,zero				# set argc to 0
  	jal	main				# call the program start function
! 	nop
  
  	# fall through to the "exit" routine
  	jal	exit				# call libc exit to run the G++
--- 207,223 ----
  	jal	_init				# run global constructors
  	nop
  
! 	addiu	a1,sp,32			# argv = sp + 32
! 	addiu	a2,sp,40			# envp = sp + 40
! #if __mips64
! 	sd	zero,(a1)			# argv[argc] = 0
! 	sd	zero,(a2)			# envp[0] = 0
! #else
! 	sw	zero,(a1)
! 	sw	zero,(a2)
! #endif
  	jal	main				# call the program start function
! 	move	a0,zero				# set argc to 0
  
  	# fall through to the "exit" routine
  	jal	exit				# call libc exit to run the G++