segregs.hpp File Reference

Functions that deal with the segment registers. More...

Classes
struct	sreg_range_t
	The values of the segment registers are kept as address ranges. More...

Macros
#define	SR_inherit   1
	the value is inherited from the previous range
#define	SR_user   2
	the value is specified by the user
#define	SR_auto   3
	the value is determined by IDA
#define	SR_autostart   4
	used as SR_auto for segment starting address

Functions
idaman sel_t ida_export	get_sreg (ea_t ea, int rg)
	Get value of a segment register. More...
idaman bool ida_export	split_sreg_range (ea_t ea, int rg, sel_t v, uchar tag, bool silent=false)
	Create a new segment register range. More...
idaman bool ida_export	set_default_sreg_value (segment_t *sg, int rg, sel_t value)
	Set default value of a segment register for a segment. More...
idaman void ida_export	set_sreg_at_next_code (ea_t ea1, ea_t ea2, int rg, sel_t value)
	Set the segment register value at the next instruction. More...
idaman bool ida_export	get_sreg_range (sreg_range_t *out, ea_t ea, int rg)
	Get segment register range by linear address. More...
idaman bool ida_export	get_prev_sreg_range (sreg_range_t *out, ea_t ea, int rg)
	Get segment register range previous to one with address. More...
idaman void ida_export	set_default_dataseg (sel_t ds_sel)
	Set default value of DS register for all segments.
idaman size_t ida_export	get_sreg_ranges_qty (int rg)
	Get number of segment register ranges. More...
idaman bool ida_export	getn_sreg_range (sreg_range_t *out, int rg, int n)
	Get segment register range by its number. More...
idaman int ida_export	get_sreg_range_num (ea_t ea, int rg)
	Get number of segment register range by address. More...
idaman bool ida_export	del_sreg_range (ea_t ea, int rg)
	Delete segment register range started at ea. More...
idaman void ida_export	copy_sreg_ranges (int dst_rg, int src_rg, bool map_selector=false)
	Duplicate segment register ranges. More...

Detailed Description

Functions that deal with the segment registers.

If your processor doesn't use segment registers, then these functions are of no use for you. However, you should define two virtual segment registers - CS and DS (for code segment and data segment) and specify their internal numbers in the LPH structure (processor_t::reg_code_sreg and processor_t::reg_data_sreg).

Function Documentation

get_sreg()

idaman sel_t ida_export get_sreg	(	ea_t	ea,
		int	rg
	)

Get value of a segment register.

This function uses segment register range and default segment register values stored in the segment structure.

Parameters

ea	linear address in the program
rg	number of the segment register

Returns

value of the segment register, BADSEL if value is unknown.

split_sreg_range()

idaman bool ida_export split_sreg_range	(	ea_t	ea,
		int	rg,
		sel_t	v,
		uchar	tag,
		bool	silent = false
	)

Create a new segment register range.

This function is used when the IDP emulator detects that a segment register changes its value.

Parameters

ea	linear address where the segment register will have a new value. if ea==BADADDR, nothing to do.
rg	the number of the segment register
v	the new value of the segment register. If the value is unknown, you should specify BADSEL.
tag	the register info tag. see Segment register range tags
silent	if false, display a warning() in the case of failure

Returns

success

set_default_sreg_value()

idaman bool ida_export set_default_sreg_value	(	segment_t *	sg,
		int	rg,
		sel_t	value
	)

Set default value of a segment register for a segment.

Parameters

sg	pointer to segment structure if nullptr, then set the register for all segments
rg	number of segment register
value	its default value. this value will be used by get_sreg() if value of the register is unknown at the specified address.

Returns

success

set_sreg_at_next_code()

idaman void ida_export set_sreg_at_next_code	(	ea_t	ea1,
		ea_t	ea2,
		int	rg,
		sel_t	value
	)

Set the segment register value at the next instruction.

This function is designed to be called from idb_event::sgr_changed handler in order to contain the effect of changing a segment register value only until the next instruction.

It is useful, for example, in the ARM module: the modification of the T register does not affect existing instructions later in the code.

Parameters

ea1	address to start to search for an instruction
ea2	the maximal address
rg	the segment register number
value	the segment register value

get_sreg_range()

idaman bool ida_export get_sreg_range	(	sreg_range_t *	out,
		ea_t	ea,
		int	rg
	)

Get segment register range by linear address.

Parameters

out	segment register range
ea	any linear address in the program
rg	the segment register number

Returns

success

get_prev_sreg_range()

idaman bool ida_export get_prev_sreg_range	(	sreg_range_t *	out,
		ea_t	ea,
		int	rg
	)

Get segment register range previous to one with address.

Note

more efficient then get_sreg_range(reg, ea-1)

Parameters

out	segment register range
ea	any linear address in the program
rg	the segment register number

Returns

success

get_sreg_ranges_qty()

idaman size_t ida_export get_sreg_ranges_qty

(

int

rg

)

Get number of segment register ranges.

Parameters

rg	the segment register number

getn_sreg_range()

idaman bool ida_export getn_sreg_range	(	sreg_range_t *	out,
		int	rg,
		int	n
	)

Get segment register range by its number.

Parameters

out	segment register range
rg	the segment register number
n	number of range (0..qty()-1)

Returns

success

get_sreg_range_num()

idaman int ida_export get_sreg_range_num	(	ea_t	ea,
		int	rg
	)

Get number of segment register range by address.

Parameters

ea	any address in the range
rg	the segment register number

Returns

-1 if no range occupies the specified address. otherwise returns number of the specified range (0..get_srranges_qty()-1)

del_sreg_range()

idaman bool ida_export del_sreg_range	(	ea_t	ea,
		int	rg
	)

Delete segment register range started at ea.

When a segment register range is deleted, the previous range is extended to cover the empty space. The segment register range at the beginning of a segment cannot be deleted.

Parameters

ea	start_ea of the deleted range
rg	the segment register number

Returns

success

copy_sreg_ranges()

idaman void ida_export copy_sreg_ranges	(	int	dst_rg,
		int	src_rg,
		bool	map_selector = false
	)

Duplicate segment register ranges.

Parameters

dst_rg	number of destination segment register
src_rg	copy ranges from
map_selector	map selectors to linear addresses using sel2ea()