88 lines
1.6 KiB
C
88 lines
1.6 KiB
C
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/*
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* The easiest way to deal with the need for DVMA mappings is
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* to just map the entire third megabyte of RAM into DVMA space.
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* That way, dvma_mapin can just compute the DVMA alias address,
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* and dvma_mapout does nothing. Note that this assumes all
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* standalone programs stay in the range SA_MIN_VA .. SA_MAX_VA
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*/
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#include <sys/param.h>
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#define DVMA_BASE 0xFFf00000
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#define DVMA_MAPLEN 0xE0000 /* 1 MB - 128K (save MONSHORTSEG) */
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#define SA_MIN_VA 0x200000
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#define SA_MAX_VA (SA_MIN_VA + DVMA_MAPLEN)
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void
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dvma_init()
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{
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int segva, dmava, sme;
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segva = SA_MIN_VA;
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dmava = DVMA_BASE;
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while (segva < SA_MAX_VA) {
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sme = get_segmap(segva);
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set_segmap(dmava, sme);
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segva += NBSG;
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dmava += NBSG;
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}
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}
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/* Convert a local address to a DVMA address. */
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char *
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dvma_mapin(char *addr, int len)
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{
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int va = (int)addr;
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/* Make sure the address is in the DVMA map. */
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if ((va < SA_MIN_VA) || (va >= SA_MAX_VA))
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panic("dvma_mapin");
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va -= SA_MIN_VA;
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va += DVMA_BASE;
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return ((char *) va);
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}
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/* Convert a DVMA address to a local address. */
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char *
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dvma_mapout(char *addr, int len)
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{
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int va = (int)addr;
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/* Make sure the address is in the DVMA map. */
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if ((va < DVMA_BASE) || (va >= (DVMA_BASE + DVMA_MAPLEN)))
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panic("dvma_mapout");
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va -= DVMA_BASE;
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va += SA_MIN_VA;
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return ((char *) va);
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}
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extern char *alloc(int len);
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char *
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dvma_alloc(int len)
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{
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char *mem;
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mem = alloc(len);
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if (!mem)
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return(mem);
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return(dvma_mapin(mem, len));
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}
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extern void free(void *ptr, int len);
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void
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dvma_free(char *dvma, int len)
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{
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char *mem;
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mem = dvma_mapout(dvma, len);
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if (mem)
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free(mem, len);
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}
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