Bytecode callback structure. More...

#include <bytecode.h>

Public Types
enum	yasm_bytecode_special_type { YASM_BC_SPECIAL_NONE = 0, YASM_BC_SPECIAL_RESERVE, YASM_BC_SPECIAL_OFFSET, YASM_BC_SPECIAL_INSN }
	Special bytecode classifications. More...

Data Fields
void(*	destroy )(void *contents)
	Destroys the implementation-specific data. More...

void(*	print )(const void contents, FILE f, int indent_level)
	Prints the implementation-specific data (for debugging purposes). More...

void(*	finalize )(yasm_bytecode bc, yasm_bytecode prev_bc)
	Finalizes the bytecode after parsing. More...

int(*	elem_size )(yasm_bytecode *bc)
	Return elements size of a data bytecode. More...

int(*	calc_len )(yasm_bytecode bc, yasm_bc_add_span_func add_span, void add_span_data)
	Calculates the minimum size of a bytecode. More...

int(*	expand )(yasm_bytecode bc, int span, long old_val, long new_val, long neg_thres, long *pos_thres)
	Recalculates the bytecode's length based on an expanded span length. More...

int(*	tobytes )(yasm_bytecode bc, unsigned char bufp, unsigned char bufstart, void *d, yasm_output_value_func output_value, yasm_output_reloc_func output_reloc)
	Convert a bytecode into its byte representation. More...

enum yasm_bytecode_callback::yasm_bytecode_special_type	special

Detailed Description

Bytecode callback structure.

Any implementation of a specific bytecode must implement these functions and this callback structure. The bytecode implementation-specific data is stored in yasm_bytecode.contents.

Definition at line 63 of file bytecode.h.

Member Enumeration Documentation

enum yasm_bytecode_callback::yasm_bytecode_special_type

Special bytecode classifications.

Most bytecode types should use #YASM_BC_SPECIAL_NONE. Others cause special handling to kick in in various parts of yasm.

Enumerator
YASM_BC_SPECIAL_RESERVE	Bytecode reserves space instead of outputting data.
YASM_BC_SPECIAL_OFFSET	Adjusts offset instead of calculating len.
YASM_BC_SPECIAL_INSN	Instruction bytecode.

Definition at line 168 of file bytecode.h.

Field Documentation

int(* yasm_bytecode_callback::calc_len)(yasm_bytecode *bc, yasm_bc_add_span_func add_span, void *add_span_data)

Calculates the minimum size of a bytecode.

Called from yasm_bc_calc_len(). A generic fill-in for this is yasm_bc_calc_len_common(), but as this function internal errors when called, be very careful when using it! This function should simply add to bc->len and not set it directly (it's initialized by yasm_bc_calc_len() prior to passing control to this function).

Parameters

bc	bytecode
add_span	function to call to add a span
add_span_data	extra data to be passed to add_span function

Returns: 0 if no error occurred, nonzero if there was an error recognized (and output) during execution.

Note: May store to bytecode updated expressions.

Definition at line 108 of file bytecode.h.

void(* yasm_bytecode_callback::destroy)(void *contents)

Destroys the implementation-specific data.

Called from yasm_bc_destroy().

Parameters

contents yasm_bytecode.contents

Definition at line 68 of file bytecode.h.

int(* yasm_bytecode_callback::elem_size)(yasm_bytecode *bc)

Return elements size of a data bytecode.

This function should return the size of each elements of a data bytecode, for proper dereference of symbols attached to it.

Parameters

bc bytecode

Returns: 0 if element size is unknown.

Definition at line 91 of file bytecode.h.

int(* yasm_bytecode_callback::expand)(yasm_bytecode *bc, int span, long old_val, long new_val,long *neg_thres,long *pos_thres)

Recalculates the bytecode's length based on an expanded span length.

Called from yasm_bc_expand(). A generic fill-in for this is yasm_bc_expand_common(), but as this function internal errors when called, if used, ensure that calc_len() never adds a span. This function should simply add to bc->len to increase the length by a delta amount.

Parameters

bc	bytecode
span	span ID (as given to add_span in calc_len)
old_val	previous span value
new_val	new span value
neg_thres	negative threshold for long/short decision (returned)
pos_thres	positive threshold for long/short decision (returned)

Returns: 0 if bc no longer dependent on this span's length, negative if there was an error recognized (and output) during execution, and positive if bc size may increase for this span further based on the new negative and positive thresholds returned.

Note: May store to bytecode updated expressions.

Definition at line 132 of file bytecode.h.

void(* yasm_bytecode_callback::finalize)(yasm_bytecode *bc, yasm_bytecode *prev_bc)

Finalizes the bytecode after parsing.

Called from yasm_bc_finalize(). A generic fill-in for this is yasm_bc_finalize_common().

Parameters

bc	bytecode
prev_bc	bytecode directly preceding bc

Definition at line 83 of file bytecode.h.

void(* yasm_bytecode_callback::print)(const void *contents, FILE *f, int indent_level)

Prints the implementation-specific data (for debugging purposes).

Called from yasm_bc_print().

Parameters

contents	yasm_bytecode.contents
f	file
indent_level	indentation level

Definition at line 76 of file bytecode.h.

int(* yasm_bytecode_callback::tobytes)(yasm_bytecode *bc, unsigned char **bufp, unsigned char *bufstart, void *d, yasm_output_value_func output_value,yasm_output_reloc_func output_reloc)

Convert a bytecode into its byte representation.

Called from yasm_bc_tobytes(). A generic fill-in for this is yasm_bc_tobytes_common(), but as this function internal errors when called, be very careful when using it!

Parameters

bc	bytecode
bufp	byte representation destination buffer; should be incremented as it's written to, so that on return its delta from the passed-in buf matches the bytecode length (it's okay not to do this if an error indication is returned)
bufstart	For calculating the correct offset parameter for the output_value calls: *bufp - bufstart.
d	data to pass to each call to output_value/output_reloc
output_value	function to call to convert values into their byte representation
output_reloc	function to call to output relocation entries for a single sym

Returns: Nonzero on error, 0 on success.

Note: May result in non-reversible changes to the bytecode, but it's preferable if calling this function twice would result in the same output.

Definition at line 159 of file bytecode.h.

The documentation for this struct was generated from the following file:

libyasm/bytecode.h

Public Types

Data Fields

Detailed Description

Member Enumeration Documentation

Field Documentation