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Diffstat (limited to 'libgloss/sparc/crt0.S')
| -rw-r--r-- | libgloss/sparc/crt0.S | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/libgloss/sparc/crt0.S b/libgloss/sparc/crt0.S new file mode 100644 index 000000000..90e18c513 --- /dev/null +++ b/libgloss/sparc/crt0.S @@ -0,0 +1,186 @@ +/* + * 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. |