48 lines
720 B
C
48 lines
720 B
C
#include <cpm.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <unistd.h>
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#define OUT_OF_MEMORY (void*)(-1) /* sbrk returns this on failure */
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extern uint8_t _end[1];
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int brk(void* newend)
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{
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uint8_t* p = newend;
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if ((p >= cpm_ramtop) ||
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(p < _end))
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return -1;
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cpm_ram = (uint8_t*)p;
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return 0;
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}
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void* sbrk(int increment)
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{
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uint8_t* old;
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uint8_t* new;
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if (increment == 0)
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return cpm_ram;
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old = cpm_ram;
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new = old + increment;
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if ((increment > 0) && (new <= old))
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goto out_of_memory;
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else if ((increment < 0) && (new >= old))
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goto out_of_memory;
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if (brk(new) < 0)
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goto out_of_memory;
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return old;
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out_of_memory:
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errno = ENOMEM;
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return OUT_OF_MEMORY;
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}
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