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https://github.com/mikpe/pdp10-tools.git
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77 lines
1.9 KiB
C
77 lines
1.9 KiB
C
/*
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* pdp10-virt-mem.c -- virtual memory simulation for PDP10
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* Copyright (C) 2018 Mikael Pettersson
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*
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* This file is part of pdp10-tools.
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*
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* pdp10-tools 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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*
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* pdp10-tools 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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*
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* You should have received a copy of the GNU General Public License
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* along with pdp10-tools. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <string.h>
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#include "pdp10-virt-mem.h"
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int pdp10_vmem_init(struct pdp10_vmem *vmem)
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{
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memset(vmem, 0, sizeof *vmem);
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return 0;
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}
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static inline pdp10_uint36_t pdp10_mword_read(uint64_t *mword)
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{
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return *mword;
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}
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static inline void pdp10_mword_write(uint64_t *mword, pdp10_uint36_t word)
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{
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/* TODO: assert high bits are clear */
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*mword = word;
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}
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static inline uint64_t *deref(struct pdp10_vmem *vmem, uint32_t address)
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{
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struct pdp10_section *section;
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struct pdp10_page *page;
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section = vmem->section[address >> 18];
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if (section) {
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page = section->page[(address >> 9) & ((1 << 9) - 1)];
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if (page)
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return &page->mword[address & ((1 << 9) - 1)];
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}
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return NULL;
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}
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uint64_t pdp10_vmem_read(struct pdp10_vmem *vmem, uint32_t address)
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{
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uint64_t *mword;
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mword = deref(vmem, address);
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if (!mword)
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return (uint64_t)-1;
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return pdp10_mword_read(mword);
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}
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int pdp10_vmem_write(struct pdp10_vmem *vmem, uint32_t address, pdp10_uint36_t word)
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{
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uint64_t *mword;
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mword = deref(vmem, address);
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if (!mword)
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return -1;
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pdp10_mword_write(mword, word);
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return 0;
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}
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