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/*
* C startup code for the Fujitsu SPARClite demo board
*
* Copyright (c) 1995, 1996 Cygnus Support
*
* The authors hereby grant permission to use, copy, modify, distribute,
* and license this software and its documentation for any purpose, provided
* that existing copyright notices are retained in all copies and that this
* notice is included verbatim in any distributions. No written agreement,
* license, or royalty fee is required for any of the authorized uses.
* Modifications to this software may be copyrighted by their authors
* and need not follow the licensing terms described here, provided that
* the new terms are clearly indicated on the first page of each file where
* they apply.
*/
#include "asm.h"
.data
.align 8
.ascii "DaTa" ! this is the first address in the data section
.long SYM(sdata)
SYM(environ):
.long 0
.text
.align 8
.globl SYM(_start)
SYM(_start):
.globl SYM(start)
SYM(start):
/* see if the stack is already setup. if not, then default
* to using the value of %sp as set by the ROM monitor
*/
sethi %hi(__stack), %g1
or %g1,%lo(__stack),%g1
cmp %g0,%g1
be 1f
mov %g1, %sp ! set the stack pointer
mov %sp, %fp
1:
/* zero the bss section */
sethi %hi(__bss_start),%g2
or %g2,%lo(__bss_start),%g2 ! start of bss
sethi %hi(_end),%g3
or %g3,%lo(_end),%g3 ! end of bss
mov %g0,%g1 ! so std has two zeros
zerobss:
std %g0,[%g2]
add %g2,8,%g2
cmp %g2,%g3
bleu,a zerobss
nop
/*
* copy prom & trap vectors to sram.
*/
set 0x30000000, %l0
set 0xfff8, %l1
tst %l1 ! Set condition codes
copyloop:
ldd [%l1], %l2
std %l2, [%l0 + %l1]
bg copyloop
deccc 8, %l1
set 0x30000000, %l0 ! Base of new trap vector
mov %l0, %tbr ! Install the new tbr
set SYM(win_ovf_trap), %l1 ! Setup window overflow trap
ldd [%l1], %l2
std %l2, [%l0 + 5 * 16]
ldd [%l1 + 8], %l2
std %l2, [%l0 + 5 * 16 + 8]
set SYM(win_unf_trap), %l1 ! Setup window underflow trap
ldd [%l1], %l2
std %l2, [%l0 + 6 * 16]
ldd [%l1 + 8], %l2
std %l2, [%l0 + 6 * 16 + 8]
/*
* Try enabling the FPU by setting EF. If that causes a trap, then we probably
* don't have an FPU.
*/
ldd [%l0 + 2 * 16], %l4 ! Save original trap routine
set SYM(no_fpu_trap), %l1 ! Install new one
ldd [%l1], %l2
std %l2, [%l0 + 2 * 16]
mov %psr, %l0
sethi %hi(0x1000), %l1
bset %l1, %l0
! mov %l0, %psr
std %l4, [2 * 16] ! Restore original trap routine
/*
* Move the data segment from it's ROM address to RAM where it
* belongs.
*/
relocd:
#if 0 /* This code is broken. FIXME */
set (_sdata),%g2 ! %g2 = start of data in aout file
set SYM(environ),%g4 ! %g4 = actual data base address
set (_edata),%g3 ! %g3 = end of where data should go
subcc %g3, %g4, %g5 ! %g5 = length of data
subcc %g4, %g2, %g0 ! need to relocate data ?
ble init
ld [%g4], %g6
subcc %g6, 1, %g0
be init
mvdata:
subcc %g5, 8, %g5
ldd [%g2 + %g5], %g6
bg mvdata
#endif
/*
* initialize target specific stuff. Only execute these
* functions it they exist.
*/
init:
sethi %hi(SYM(hardware_init_hook)), %g1
or %g1,%lo(SYM(hardware_init_hook)),%g1
cmp %g0,%g1
be 1f
nop
call SYM(hardware_init_hook)
nop
1:
sethi %hi(SYM(software_init_hook)), %g1
or %g1,%lo(SYM(software_init_hook)),%g1
cmp %g0,%g1
be 2f
nop
call SYM(software_init_hook)
nop
2:
call SYM(main)
nop
/* call exit from the C library so atexit gets called, and the
* C++ destructors get run. This calls our exit routine below
* when it's done.
*/
call SYM(exit)
nop
/*
* This should drop control back to the ROM monitor, if there is
* one.
*/
.globl SYM(_exit)
SYM(_exit):
call 0
nop
/*
* Trap handlers.
*/
.align 8
SYM(win_ovf_trap):
sethi %hi(SYM(win_ovf)), %l3
jmpl %lo(SYM(win_ovf))+%l3, %g0
mov %wim, %l0
nop
SYM(win_unf_trap):
sethi %hi(SYM(win_unf)), %l3
jmpl %lo(SYM(win_unf))+%l3, %g0
mov %wim, %l0
nop
SYM(no_fpu_trap): ! Come here when no fpu exists.
jmpl %l2, %g0 ! This just skips the
rett %l2+4 ! offending instruction.
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