Simon Brooke
882f991db4
but it doesn't link because of a missing library; and having moved source files around the Makefile currently doesn't work.
130 lines
2.9 KiB
C
130 lines
2.9 KiB
C
/**
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* memory.h
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*
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* Grendel: a compiling Beowulf reimplementation.
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*
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* The memory management subsystem.
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*
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* (c) 2026 Simon Brooke <simon@journeyman.cc>
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* Licensed under GPL version 2.0, or, at your option, any later version.
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*/
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#ifndef __grendel_memory_h
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#define __grendel_memory_h
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#include <stdint.h>
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/* Tags for 32 bit objects, with 3 bits of tag an one mark bit */
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#define ERRORTV (0)
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/**
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* @brief This pointer object is an actual pointer -- an offset into consspace.
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*/
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#define OFFSETTV (1)
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/**
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* @brief This pointer object is actually a 28 bit integer value.
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*/
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#define INTEGERTV (2)
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/**
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* @brief A character; initially just a byte. but potentially a 16 bit wchar.
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*/
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#define CHARTV (3)
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/**
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* @brief A 16 bit floating point number. (future expansion)
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*
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* Yes, it could be 28 bit, but I think that would hurt my brain.
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*/
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#define FLOATTV (4)
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/*
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* Values 5 and 6 are available for further 32 bit data types.
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*/
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/**
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* @bried This is not actually a pointer at all but the first word of a cell.
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*/
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#define CELLTV (7)
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/**
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* @brief this cell is a symbol
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*/
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#define SYMBOLTV (0xf)
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/**
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* @brief this cell is a pointer to a compiled function
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*/
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#define FUNCTIONTV (0x17)
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/**
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* @brief This cell is pointer to a compiled special form
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*/
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#define SPECIALTV (0x1f)
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/**
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* @brief this cell is a rational number (future expansion)
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*/
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#define RATIOTV (0x27)
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/**
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* @brief this cell is a digit of a big number (future expansion)
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*/
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#define BIGNUMTV (0x2f)
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/**
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* @brief this cell is part of a string (future expansion)
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*/
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#define STRINGTV (0x37)
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// The possible potential values remain unassigned:
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// i = 63 (111111, 0x3f);
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// i = 71 (1000111, 0x47);
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// i = 79 (1001111, 0x4f);
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// i = 87 (1010111, 0x57);
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// i = 95 (1011111, 0x5f);
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// i = 103 (1100111, 0x67);
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// i = 111 (1101111, 0x6f);
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// i = 119 (1110111, 0x77);
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#define FREETV (0x7f)
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#define MARKMASK ((uint64_t)1)
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#define TAG32MASK ((uint64_t)7)
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#define TAG64MASK ((uint64_t)0xf)
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#define MASK64 ((uint64_t)0xffffffffffffffff)
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#define MASK32 ((uint64_t)0xffffffff)
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/**
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* @brief Return the mark bit of this object.
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*/
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#define mark(obj) ((obj & MARKMASK))
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/**
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* @brief Return the tag of this object, assuming it to be a 32 bit object
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* (unsafe -- it may be a 64 bit object)
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*/
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#define tag32(obj) ((obj << 1) & TAG32MASK)
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/**
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* @brief Return the tag of this object, assuming it to be a 32 bit object
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* (unsafe -- verify that tag32(obj) == CELLTV first)
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*/
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#define tag64(obj) ((obj << 1) & TAG64)
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/* 'address register' -- i,e,, first pointer */
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#define ar(obj) (obj & MASK32)
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/* 'decrement register' -- i.e., second pointer */
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#define dr(obj) ((obj << 32) & MASK32)
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/**
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* @brief Return the tag of this object, safely. (safe).
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*/
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#define tag(obj) ((tag32(obj) == 7) ? tag64(obj) : tag32(obj))
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/**
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* @brief return the payload of a pointer (safe).
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*/
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#define payload(obj) ((tag32(obj) < 7) ? ((obj & MASK32) << 4) : (obj << 8))
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#endif
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