138 lines
3.8 KiB
C
138 lines
3.8 KiB
C
/*
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Copyright 2012 Wolfgang Thaller.
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This file is part of Retro68.
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Retro68 is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Retro68 is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with Retro68. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdint.h>
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#include <Processes.h>
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#include <Sound.h>
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#include <Memory.h>
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#include <OSUtils.h>
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int main(int argc, char* argv[]);
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struct flat_hdr {
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char magic[4];
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unsigned long rev; /* version */
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unsigned long entry; /* Offset of first executable instruction
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with text segment from beginning of file */
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unsigned long data_start; /* Offset of data segment from beginning of
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file */
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unsigned long data_end; /* Offset of end of data segment
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from beginning of file */
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unsigned long bss_end; /* Offset of end of bss segment from beginning
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of file */
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/* (It is assumed that data_end through bss_end forms the bss segment.) */
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unsigned long stack_size; /* Size of stack, in bytes */
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unsigned long reloc_start; /* Offset of relocation records from
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beginning of file */
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unsigned long reloc_count; /* Number of relocation records */
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unsigned long flags;
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unsigned long filler[6]; /* Reserved, set to zero */
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};
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typedef void (*voidFunction)(void);
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extern void __init_section(void);
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extern void __init_section_end(void);
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extern void __fini_section(void);
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extern void __fini_section_end(void);
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void _start()
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{
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long virtualstart, realstart;
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__asm__( "move.l #_start, %0" : "=r"(virtualstart) );
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__asm__( "lea (_start:w,%%pc), %0" : "=a"(realstart) );
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long displacement = realstart - virtualstart;
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struct flat_hdr *header = (struct flat_hdr*) (displacement - 0x40);
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SysEnvRec env;
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long bss_size;
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Ptr bss;
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env.processor = 0;
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__asm__ __volatile__ (
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"move.w #2, %%d0\n\t" // versionRequested
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"lea %0, %%a0\n\t" // &env
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"dc.w 0xa090\n\t" // _SysEnvirons
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:
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: "m"(env)
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: "%a0", "%a1", "%d0", "%d1", "%d2", "memory", "cc"
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);
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bss_size = header->bss_end - header->data_end;
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//Ptr bss = NewPtrClear(bss_size);
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__asm__ __volatile__ (
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"move.l %1, %%d0\n\t"
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"dc.w 0xa31e\n\t" // _NewPtrClear
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"move.l %%a0 , %0\n\t"
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: "=g"(bss)
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: "g"(bss_size)
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: "%a0", "%a1", "%d0", "%d1", "%d2", "memory", "cc"
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);
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long n = header->reloc_count;
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long *relocs = (long*)( (char*)header + header->reloc_start );
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long i;
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long data_end = header->data_end - 0x40;
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long bss_displacement = (long)bss - data_end;
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for(i = 0; i < n; i++)
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{
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uint8_t *addrPtr = (uint8_t*)(relocs[i] + displacement);
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long addr;
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addr = (addrPtr[0] << 24) | (addrPtr[1] << 16) | (addrPtr[2] << 8) | addrPtr[3];
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addr += addr >= data_end ? bss_displacement : displacement;
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addrPtr[0] = addr >> 24;
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addrPtr[1] = addr >> 16;
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addrPtr[2] = addr >> 8;
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addrPtr[3] = addr;
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}
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if(env.processor >= env68040)
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{
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__asm__ __volatile__ ("dc.w 0xa0bd" : : : "%a0", "%a1", "%d0", "%d1", "%d2", "cc"); // FlushCache();
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}
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{
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char *p = (char*)&__init_section;
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char *e = (char*)&__init_section_end;
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p += 2;
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while( p < e )
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{
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(*(voidFunction)(*(long*)p))();
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p += 6;
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}
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}
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{
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char *argv[2] = { "./a.out", NULL };
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main(1, argv);
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}
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ExitToShell();
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}
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