71 lines
1.2 KiB
C
71 lines
1.2 KiB
C
#include <string.h>
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#include <stdio.h>
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#include <c64/asm6502.h>
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// Invoke resident section with "SYS 49152" from basic
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// not much space, so we go with a smaller stack size
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#pragma stacksize(256)
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// shrink size of startup section
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#pragma section(startup, 0);
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#pragma region(startup, 0x0801, 0x0870, , , { startup } )
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// section for code copy
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#pragma section(rcode, 0)
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#pragma region(rcode, 0x0870, 0x0900, , , { rcode } )
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// main section to stay resident, save three bytes at the
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// beginning to have space for an entry jump
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#pragma region(main, 0x0903, 0x1900, , , {code, data, bss, heap, stack}, 0xc003 )
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// resident entry routine
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void tsr(void)
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{
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// Initialize stack pointer
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__asm {
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lda #$ff
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sta __sp
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lda #$cf
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sta __sp +1
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}
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// do something useless
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printf(p"Hello World\n");
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// and done
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}
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// Now the copy code section
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#pragma code(rcode)
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int main(void)
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{
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// source and target address to copy, no memcpy as it is itself
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// not yet copied
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char * dp = (char *)0xc000;
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char * sp = (char *)0x0903;
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// A jmp to the code at the absolute address 0xc000 / 49152
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dp += asm_ab(dp, ASM_JMP, (unsigned)tsr);
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// then the code
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for(unsigned i=0; i<0xffd; i++)
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*dp++ = *sp++;
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// now we are done
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return 0;
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}
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