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