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Diffstat (limited to 'c/src/lib/start/m68k/start.s')
| -rw-r--r-- | c/src/lib/start/m68k/start.s | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/c/src/lib/start/m68k/start.s b/c/src/lib/start/m68k/start.s new file mode 100644 index 0000000000..0bbb0a851f --- /dev/null +++ b/c/src/lib/start/m68k/start.s @@ -0,0 +1,160 @@ +/* entry.s + * + * This file contains the entry point for the application. + * The name of this entry point is compiler dependent. + * It jumps to the BSP which is responsible for performing + * all initialization. + * + * COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994. + * On-Line Applications Research Corporation (OAR). + * All rights assigned to U.S. Government, 1994. + * + * This material may be reproduced by or for the U.S. Government pursuant + * to the copyright license under the clause at DFARS 252.227-7013. This + * notice must appear in all copies of this file and its derivatives. + * + * $Id$ + */ + +#include "asm.h" + +BEGIN_CODE + | Default entry points for: + PUBLIC (start) | GNU + PUBLIC (M68Kvec) | Vector Table + +SYM (start): +SYM (M68Kvec): | standard location for vectors + nop | for linkers with problem + | location zero + jmp SYM (start_around) + + /* + * We can use the following space as our vector table + * if the CPU has a VBR or we can save vector table in it + * if the CPU does not. + */ + + .space 4088 | to avoid initial intr stack + | from 135BUG on MVME13? + | and start code at 0x4000 +SYM (vectors): + .space 1016 | reserve space for rest of vectors + +#if ( M68K_HAS_SEPARATE_STACKS == 1 ) +SYM (lowintstack): + .space 4092 | reserve for interrupt stack +SYM (hiintstack): + .space 4 | end of interrupt stack +#endif + + PUBLIC (start_around) +SYM (start_around): + move.w sr, SYM (initial_sr) +#if ( M68K_HAS_SEPARATE_STACKS == 1 ) + movec isp,a0 + move.l a0, SYM (initial_isp) + movec usp,a0 + move.l a0, SYM (initial_usp) + movec msp,a0 + move.l a0, SYM (initial_msp) +#else + move.l a7, SYM (initial_msp) +#endif + oriw #0x0700,sr | INTERRUPTS OFF!!! + + + + | + | zero out uninitialized data area + | +zerobss: + moveal # SYM (end),a0 | find end of .bss + moveal # SYM (bss_start),a1 | find beginning of .bss + movel #0,d0 + +loop: movel #0,a1@+ | to zero out uninitialized + cmpal a0,a1 + jlt loop | loop until _end reached + + movel # SYM (end),d0 | d0 = end of bss/start of heap + addl # SYM (heap_size),d0 | d0 = end of heap + movel d0, SYM (stack_start) | Save for brk() routine + addl # SYM (stack_size),d0 | make room for stack + andl #0xffffffc0,d0 | align it on 16 byte boundary + movw #0x3700,sr | SUPV MODE,INTERRUPTS OFF!!! + movel d0,a7 | set master stack pointer + movel d0,a6 | set base pointer + + /* + * RTEMS should maintiain a separate interrupt stack on CPUs + * without one in hardware. This is currently not supported + * on versions of the m68k without a HW intr stack. + */ + +#if ( M68K_HAS_SEPARATE_STACKS == 1 ) + lea SYM (hiintstack),a0 | a0 = high end of intr stack + movec a0,isp | set interrupt stack +#endif + + jsr SYM (bsp_start) +#if ( M68K_HAS_SEPARATE_STACKS == 1 ) + move.l SYM (initial_isp),a0 + movec a0,isp + move.l SYM (initial_usp),a0 + movec a0,usp + move.l SYM (initial_msp),a0 + movec a0,msp +#else + movea.l SYM (initial_msp),a7 +#endif + move.w SYM (initial_sr),sr + rts + +END_CODE + +BEGIN_DATA + + PUBLIC (start_frame) +SYM (start_frame): + .space 4,0 + + PUBLIC (stack_start) +SYM (stack_start): + .space 4,0 +END_DATA + +BEGIN_BSS + + PUBLIC (environ) + .align 2 +SYM (environ): + .long 0 + + PUBLIC (initial_isp) +SYM (initial_isp): + .space 4 + + PUBLIC (initial_msp) +SYM (initial_msp): + .space 4 + + PUBLIC (initial_usp) +SYM (initial_usp): + .space 4 + + PUBLIC (initial_sr) +SYM (initial_sr): + .space 2 + + PUBLIC (heap_size) + .set SYM (heap_size),0x2000 + + PUBLIC (stack_size) + .set SYM (stack_size),0x1000 + + +END_DATA +END + + |