Trying to build a forth runtime in C
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forth/include/fh_runtime.h

206 lines
5.2 KiB

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/**
* Forth runtime internals
*
* Created on 2021/11/13.
*/
#ifndef FORTH_FH_RUNTIME_H
#define FORTH_FH_RUNTIME_H
#include <stdint.h>
#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>
#include "fh_config.h"
struct fh_word_s;
struct fh_instruction_s;
struct fh_thread_s;
/** Word handler typedef */
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typedef enum fh_error (*word_exec_t)(struct fh_thread_s *fh, const struct fh_word_s *w);
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/** Bytecode instruction type marker */
enum fb_instruction_kind {
/* Data = word pointer (dict index) */
FH_INSTR_WORD,
/* Data = numeric value to push onto the data stack */
FH_INSTR_NUMBER,
/** End of a user defined word, pop address and jump back */
FH_INSTR_ENDWORD,
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/** This is the `s"` instruction, the length (u32) and string data immediately follow */
FH_INSTR_ALLOCSTR,
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/** This is the `."` instruction, same format as above. */
FH_INSTR_TYPESTR,
/* Unconditional jump */
FH_INSTR_JUMP,
/* Jump if zero */
FH_INSTR_JUMPZERO,
/* Postponed word */
FH_INSTR_POSTPONED_WORD,
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};
/** One instruction in bytecode */
struct fh_instruction_s {
/** What is the meaning of data? */
enum fb_instruction_kind kind;
/** Data word */
uint32_t data;
};
static inline void instr_init(struct fh_instruction_s *instr, enum fb_instruction_kind kind, uint32_t data)
{
instr->kind = kind;
instr->data = data;
}
#define INSTR_SIZE (sizeof(struct fh_instruction_s))
_Static_assert(sizeof(struct fh_instruction_s) % 4 == 0, "Instruction struct is aligned");
/** Forth runtime major state */
enum fh_state {
/** Interactive interpret mode */
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FH_STATE_INTERPRET = 0,
/** Compiling */
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FH_STATE_COMPILE,
/** Quit from RUN to interpret */
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FH_STATE_QUIT,
/** Shutting down the runtime */
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FH_STATE_SHUTDOWN,
FH_STATE_MAX,
};
/** Forth runtime minor state */
enum fh_substate {
FH_SUBSTATE_NONE = 0,
FH_SUBSTATE_COLON_NAME,
FH_SUBSTATE_S_QUOTE,
FH_SUBSTATE_DOT_QUOTE,
FH_SUBSTATE_PAREN_COMMENT,
FH_SUBSTATE_LINE_COMMENT,
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FH_SUBSTATE_EXIT,
FH_SUBSTATE_SEE_NAME,
FH_SUBSTATE_POSTPONE_NAME,
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FH_SUBSTATE_MAX,
};
/** Word struct as they are stored in the dictionary */
struct fh_word_s {
uint32_t index;
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/** Word name */
char name[MAX_NAME_LEN];
/**
* Handler function.
* Builtin functions use pre-defined native handlers.
* User words use a shared handler that executes compiled
* bytecode at 'start' address of the compile-memory area.
*/
word_exec_t handler;
/** Indicates that this is a built-in instruction and not a word call */
bool builtin;
/** Indicates that this instruction should always be treated as interpreted,
* in practice this is only used for `;` */
bool immediate;
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/** Start address in case of user words, or param for builtins */
union {
uint32_t start;
uint32_t param;
};
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};
/**
* Forth runtime instance - state variables and memory areas.
*
* Some memory areas, such as the dict or heap, could be moved
* to a shared pointer if multi-threading and synchronization is added.
*/
struct fh_thread_s {
/** Control stack */
uint32_t control_stack[CONTROL_STACK_DEPTH];
size_t control_stack_top;
size_t control_stack_hwm;
/** Data stack */
uint32_t data_stack[DATA_STACK_DEPTH];
size_t data_stack_top;
size_t data_stack_hwm;
/** Return stack */
uint32_t return_stack[RETURN_STACK_DEPTH];
size_t return_stack_top;
size_t return_stack_hwm;
/** Data heap */
uint8_t heap[HEAP_SIZE];
size_t heap_top;
/** Compile buffer, used for both word data and literals */
uint8_t compile[COMPILED_BUFFER_SIZE];
size_t compile_top;
/** Pointer into the compile buffer for execution */
uint32_t execptr;
/** Word dict */
struct fh_word_s dict[DICT_SIZE];
uint32_t dict_top;
/** Forth state */
enum fh_state state;
/** Forth sub-state */
enum fh_substate substate;
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/** The numeric base register */
uint32_t base;
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};
enum fh_error fh_add_word(const struct fh_word_s *w, struct fh_thread_s *fh);
void fh_setstate(struct fh_thread_s *fh, enum fh_state state, enum fh_substate substate);
void fh_setsubstate(struct fh_thread_s *fh, enum fh_substate substate);
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enum fh_error w_user_word(struct fh_thread_s *fh, const struct fh_word_s *w);
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/* if the return address is this, we should drop back to interactive mode */
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// SFR and magic addresses are "negative"
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#define MAGICADDR_INTERACTIVE 0xFFFFFFFFULL
#define MAGICADDR_BASE 0xFFFFBA5EULL
#define MAGICADDR_UNRESOLVED 0xFFFFFBADULL
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/** Get a value rounded up to multiple of word size */
#define WORDALIGNED(var) (((var) + 3) & ~3)
_Static_assert(WORDALIGNED(0) == 0, "word align");
_Static_assert(WORDALIGNED(1) == 4, "word align");
_Static_assert(WORDALIGNED(2) == 4, "word align");
_Static_assert(WORDALIGNED(3) == 4, "word align");
_Static_assert(WORDALIGNED(4) == 4, "word align");
_Static_assert(WORDALIGNED(5) == 8, "word align");
_Static_assert(WORDALIGNED(1023) == 1024, "word align");
_Static_assert(WORDALIGNED(1024) == 1024, "word align");
#define TRY(x) \
do { \
if (FH_OK != (rv = (x))) return rv; \
} while (0)
enum fh_error fh_handle_ascii_word(
struct fh_thread_s *fh,
const char *name,
size_t wordlen
);
enum fh_error fh_handle_word(struct fh_thread_s *fh, const struct fh_word_s *w);
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#endif //FORTH_FH_RUNTIME_H