2 * *****************************************************************************
4 * SPDX-License-Identifier: BSD-2-Clause
6 * Copyright (c) 2018-2021 Gavin D. Howard and contributors.
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9 * modification, are permitted provided that the following conditions are met:
11 * * Redistributions of source code must retain the above copyright notice, this
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15 * this list of conditions and the following disclaimer in the documentation
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30 * *****************************************************************************
32 * Definitions for program data.
49 /// The instructions for bytecode.
54 /// Postfix increment and decrement. Prefix are translated into
55 /// BC_INST_ONE with either BC_INST_ASSIGN_PLUS or BC_INST_ASSIGN_MINUS.
65 #if BC_ENABLE_EXTRA_MATH
66 /// Truncation operator.
68 #endif // BC_ENABLE_EXTRA_MATH
70 /// These should be self-explanatory.
78 #if BC_ENABLE_EXTRA_MATH
86 #endif // BC_ENABLE_EXTRA_MATH
88 /// Comparison operators.
96 /// Boolean or and and.
101 /// Same as the normal operators, but assigment. So ^=, *=, /=, etc.
102 BC_INST_ASSIGN_POWER,
103 BC_INST_ASSIGN_MULTIPLY,
104 BC_INST_ASSIGN_DIVIDE,
105 BC_INST_ASSIGN_MODULUS,
107 BC_INST_ASSIGN_MINUS,
108 #if BC_ENABLE_EXTRA_MATH
109 /// Places and shift assignment operators.
110 BC_INST_ASSIGN_PLACES,
111 BC_INST_ASSIGN_LSHIFT,
112 BC_INST_ASSIGN_RSHIFT,
113 #endif // BC_ENABLE_EXTRA_MATH
115 /// Normal assignment.
118 /// bc and dc detect when the value from an assignment is not necessary.
119 /// For example, a plain assignment statement means the value is never used.
120 /// In those cases, we can get lots of performance back by not even creating
121 /// a copy at all. In fact, it saves a copy, a push onto the results stack,
122 /// a pop from the results stack, and a free. Definitely worth it to detect.
123 BC_INST_ASSIGN_POWER_NO_VAL,
124 BC_INST_ASSIGN_MULTIPLY_NO_VAL,
125 BC_INST_ASSIGN_DIVIDE_NO_VAL,
126 BC_INST_ASSIGN_MODULUS_NO_VAL,
127 BC_INST_ASSIGN_PLUS_NO_VAL,
128 BC_INST_ASSIGN_MINUS_NO_VAL,
129 #if BC_ENABLE_EXTRA_MATH
131 BC_INST_ASSIGN_PLACES_NO_VAL,
132 BC_INST_ASSIGN_LSHIFT_NO_VAL,
133 BC_INST_ASSIGN_RSHIFT_NO_VAL,
134 #endif // BC_ENABLE_EXTRA_MATH
137 /// Normal assignment that pushes no value on the stack.
138 BC_INST_ASSIGN_NO_VAL,
140 /// Push a constant onto the results stack.
143 /// Push a variable onto the results stack.
146 /// Push an array element onto the results stack.
149 /// Push an array onto the results stack. This is different from pushing an
150 /// array *element* onto the results stack; it pushes a reference to the
151 /// whole array. This is needed in bc for function arguments that are
152 /// arrays. It is also needed for returning the length of an array.
155 /// Push a zero or a one onto the stack. These are special cased because it
156 /// does help performance, particularly for one since inc/dec operators
162 /// Push the last printed value onto the stack.
166 /// Push the value of any of the globals onto the stack.
171 #if BC_ENABLE_EXTRA_MATH
172 /// Push the value of the seed global onto the stack.
174 #endif // BC_ENABLE_EXTRA_MATH
176 /// These are builtin functions.
182 #if BC_ENABLE_EXTRA_MATH
183 /// Another builtin function.
185 #endif // BC_ENABLE_EXTRA_MATH
190 /// Another builtin function.
193 #if BC_ENABLE_EXTRA_MATH
194 /// Another builtin function.
196 #endif // BC_ENABLE_EXTRA_MATH
198 /// Return the max for the various globals.
202 #if BC_ENABLE_EXTRA_MATH
203 /// Return the max value returned by rand().
205 #endif // BC_ENABLE_EXTRA_MATH
207 /// bc line_length() builtin function.
212 /// bc global_stacks() builtin function.
213 BC_INST_GLOBAL_STACKS,
217 /// bc leading_zero() builtin function.
218 BC_INST_LEADING_ZERO,
220 /// This is slightly misnamed versus BC_INST_PRINT_POP. Well, it is in bc.
221 /// dc uses this instruction to print, but not pop. That's valid in dc.
222 /// However, in bc, it is *never* valid to print without popping. In bc,
223 /// BC_INST_PRINT_POP is used to indicate when a string should be printed
224 /// because of a print statement or whether it should be printed raw. The
225 /// reason for this is because a print statement handles escaped characters.
226 /// So BC_INST_PRINT_POP is for printing a string from a print statement,
227 /// BC_INST_PRINT_STR is for printing a string by itself.
229 /// In dc, BC_INST_PRINT_POP prints and pops, and BC_INST_PRINT just prints.
231 /// Oh, and BC_INST_STR pushes a string onto the results stack.
238 /// Jumps unconditionally.
241 /// Jumps if the top of the results stack is zero (condition failed). It
242 /// turns out that we only want to jump when conditions fail to "skip" code.
248 /// Return the top of the stack to the caller.
251 /// Return 0 to the caller.
254 /// Special return instruction for void functions.
257 /// Special halt instruction.
261 /// Pop an item off of the results stack.
264 /// Swaps the top two items on the results stack.
267 /// Modular exponentiation.
270 /// Do divide and modulus at the same time.
273 /// Turns a number into a string and prints it.
274 BC_INST_PRINT_STREAM,
278 /// dc's return; it pops an executing string off of the stack.
281 /// Unconditionally execute a string.
284 /// Conditionally execute a string.
287 /// Prints each item on the results stack, separated by newlines.
290 /// Pops everything off of the results stack.
293 /// Pushes the current length of a register stack onto the results stack.
294 BC_INST_REG_STACK_LEN,
296 /// Pushes the current length of the results stack onto the results stack.
299 /// Pushes a copy of the item on the top of the results stack onto the
303 /// Copies the value in a register and pushes the copy onto the results
307 /// Pops an item off of a register stack and pushes it onto the results
311 /// Pops an item off of the results stack and pushes it onto a register's
318 /// Quit executing some number of strings.
321 /// Push the depth of the execution stack onto the stack.
322 BC_INST_EXEC_STACK_LEN,
326 /// Invalid instruction.
332 _Static_assert(BC_INST_INVALID <= UCHAR_MAX,
333 "Too many instructions to fit into an unsigned char");
336 /// Used by maps to identify where items are in the array.
339 /// The name of the item.
342 /// The index into the array where the item is.
347 /// The location of a var, array, or array element.
350 /// The index of the var or array.
353 /// The index of the array element. Only used for array elements.
358 /// An entry for a constant.
359 typedef struct BcConst
361 /// The original string as parsed from the source code.
364 /// The last base that the constant was parsed in.
367 /// The parsed constant.
372 /// A function. This is also used in dc, not just bc. The reason is that strings
373 /// are executed in dc, and they are converted to functions in order to be
375 typedef struct BcFunc
377 /// The bytecode instructions.
382 /// The labels. This is a vector of indices. The index is the index into
383 /// the bytecode vector where the label is.
386 /// The autos for the function. The first items are the parameters, and the
387 /// arguments to the parameters must match the types in this vector.
390 /// The number of parameters the function takes.
395 /// The strings encountered in the function.
398 /// The constants encountered in the function.
401 /// The function's name.
405 /// True if the function is a void function.
411 /// Types of results that can be pushed onto the results stack.
412 typedef enum BcResultType
414 /// Result is a variable.
417 /// Result is an array element.
418 BC_RESULT_ARRAY_ELEM,
420 /// Result is an array. This is only allowed for function arguments or
421 /// returning the length of the array.
424 /// Result is a string.
427 /// Result is a temporary. This is used for the result of almost all
431 /// Special casing the two below gave performance improvements.
436 /// Result is a 1. Useful for inc/dec operators.
441 /// Result is the special "last" variable.
444 /// Result is the return value of a void function.
448 /// Result is the value of ibase.
451 /// Result is the value of obase.
454 /// Result is the value of scale.
457 #if BC_ENABLE_EXTRA_MATH
459 /// Result is the value of seed.
462 #endif // BC_ENABLE_EXTRA_MATH
466 /// A union to store data for various result types.
467 typedef union BcResultData
469 /// A number. Strings are stored here too; they are numbers with
470 /// cap == 0 && num == NULL. The string's index into the strings vector is
471 /// stored in the scale field. But this is only used for strings stored in
478 /// A variable, array, or array element reference. This could also be a
479 /// string if a string is not stored in a variable (dc only).
484 /// A tagged union for results.
485 typedef struct BcResult
487 /// The tag. The type of the result.
490 /// The data. The data for the result.
495 /// An instruction pointer. This is how bc knows where in the bytecode vector,
496 /// and which function, the current execution is.
497 typedef struct BcInstPtr
499 /// The index of the currently executing function in the fns vector.
502 /// The index into the bytecode vector of the *next* instruction.
505 /// The length of the results vector when this function started executing.
506 /// This is mostly used for bc where functions should not affect the results
507 /// of their callers.
512 /// Types of identifiers.
531 /// An auto variable in bc.
532 typedef struct BcAuto
534 /// The index of the variable in the vars or arrs vectors.
537 /// The type of the variable.
543 /// Forward declaration.
547 * Initializes a function.
548 * @param f The function to initialize.
549 * @param name The name of the function. The string is assumed to be owned by
553 bc_func_init(BcFunc* f, const char* name);
556 * Inserts an auto into the function.
557 * @param f The function to insert into.
558 * @param p The program. This is to search for the variable or array name.
559 * @param name The name of the auto to insert.
560 * @param type The type of the auto.
561 * @param line The line in the source code where the insert happened. This is
562 * solely for error reporting.
565 bc_func_insert(BcFunc* f, struct BcProgram* p, char* name, BcType type,
569 * Resets a function in preparation for it to be reused. This can happen in bc
570 * because it is a dynamic language and functions can be redefined.
571 * @param f The functio to reset.
574 bc_func_reset(BcFunc* f);
578 * Frees a function. This is a destructor. This is only used in debug builds
579 * because all functions are freed at exit. We free them in debug builds to
580 * check for memory leaks.
581 * @param func The function to free as a void pointer.
584 bc_func_free(void* func);
588 * Initializes an array, which is the array type in bc and dc source code. Since
589 * variables and arrays are both arrays (see the development manual,
590 * manuals/development.md#execution, for more information), the @a nums
591 * parameter tells bc whether to initialize an array of numbers or an array of
592 * arrays of numbers. If the latter, it does a recursive call with nums set to
594 * @param a The array to initialize.
595 * @param nums True if the array should be for numbers, false if it should be
599 bc_array_init(BcVec* a, bool nums);
602 * Copies an array to another array. This is used to do pass arrays to functions
603 * that do not take references to arrays. The arrays are passed entirely by
604 * value, which means that they need to be copied.
605 * @param d The destination array.
606 * @param s The source array.
609 bc_array_copy(BcVec* d, const BcVec* s);
612 * Frees a string stored in a function. This is a destructor.
613 * @param string The string to free as a void pointer.
616 bc_string_free(void* string);
619 * Frees a constant stored in a function. This is a destructor.
620 * @param constant The constant to free as a void pointer.
623 bc_const_free(void* constant);
626 * Clears a result. It sets the type to BC_RESULT_TEMP and clears the union by
627 * clearing the BcNum in the union. This is to ensure that bc does not use
628 * uninitialized data.
629 * @param r The result to clear.
632 bc_result_clear(BcResult* r);
635 * Copies a result into another. This is done for things like duplicating the
636 * top of the results stack or copying the result of an assignment to put back
637 * on the results stack.
638 * @param d The destination result.
639 * @param src The source result.
642 bc_result_copy(BcResult* d, BcResult* src);
645 * Frees a result. This is a destructor.
646 * @param result The result to free as a void pointer.
649 bc_result_free(void* result);
652 * Expands an array to @a len. This can happen because in bc, you do not have to
653 * explicitly initialize elements of an array. If you access an element that is
654 * not initialized, the array is expanded to fit it, and all missing elements
655 * are initialized to 0 if they are numbers, or arrays with one element of 0.
656 * This function does that expansion.
657 * @param a The array to expand.
658 * @param len The length to expand to.
661 bc_array_expand(BcVec* a, size_t len);
664 * Compare two BcId's and return the result. Since they are just comparing the
665 * names in the BcId, I return the result from strcmp() exactly. This is used by
666 * maps in their binary search.
667 * @param e1 The first id.
668 * @param e2 The second id.
669 * @return The result of strcmp() on the BcId's names.
672 bc_id_cmp(const BcId* e1, const BcId* e2);
677 * Returns non-zero if the bytecode instruction i is an assignment instruction.
678 * @param i The instruction to test.
679 * @return Non-zero if i is an assignment instruction, zero otherwise.
681 #define BC_INST_IS_ASSIGN(i) \
682 ((i) == BC_INST_ASSIGN || (i) == BC_INST_ASSIGN_NO_VAL)
685 * Returns true if the bytecode instruction @a i requires the value to be
687 * @param i The instruction to test.
688 * @return True if @a i requires the value to be returned for use, false
691 #define BC_INST_USE_VAL(i) ((i) <= BC_INST_ASSIGN)
696 * Returns non-zero if the bytecode instruction i is an assignment instruction.
697 * @param i The instruction to test.
698 * @return Non-zero if i is an assignment instruction, zero otherwise.
700 #define BC_INST_IS_ASSIGN(i) ((i) == BC_INST_ASSIGN_NO_VAL)
703 * Returns true if the bytecode instruction @a i requires the value to be
705 * @param i The instruction to test.
706 * @return True if @a i requires the value to be returned for use, false
709 #define BC_INST_USE_VAL(i) (false)
714 /// Reference to string names for all of the instructions. For debugging.
715 extern const char* bc_inst_names[];
716 #endif // BC_DEBUG_CODE
718 /// References to the names of the main and read functions.
719 extern const char bc_func_main[];
720 extern const char bc_func_read[];