ubc_breakpoint_t Struct Reference

UBC breakpoint structure. More...

#include <ubc.h>

Data Fields
void *	address
	Target address.
ubc_address_mask_t	address_mask
	Address mask.
ubc_access_t	access
	Access type.
struct {
bool   break_before
	Break before instruction execution. More...
}	instruction
	Instruction access type settings.
struct {
ubc_rw_t   rw
	Read/write condition. More...
ubc_size_t   size
	Size condition. More...
struct {
bool   enabled
	Enables data value comparisons. More...
uint32_t   value
	Data value for operand accesses. More...
uint32_t   mask
	Exclusion mask for data value comparison. More...
}   data
	Optional operand data settings. More...
}	operand
	Operand access type settings.
struct {
bool   enabled
	Enables ASID value comparisons. More...
uint8_t   value
	ASID value. More...
}	asid
	Optional ASID settings.
struct ubc_breakpoint *	next
	Next breakpoint in the sequence.

Detailed Description

UBC breakpoint structure.

This structure contains all of the information needed to configure a breakpoint using the SH4's UBC. It is meant to be zero-initialized, with the most commonly preferred, general values being the defaults, so that the only member that must be initialized to a non-zero value is ubc_breakpoint_t::address.

Note

The default configuration (from zero initialization) will trigger a breakpoint with any access to ubc_breakpoint_t::address.

Warning

When using ubc_breakpoint_t::asid or ubc_breakpoint_t::data, do not forget to set their respective enable members!

Field Documentation

access

ubc_access_t ubc_breakpoint_t::access

Access type.

Controls which type of access to the target address(es) to break on.

address

void* ubc_breakpoint_t::address

Target address.

Address used as the target or base memory address of a breakpoint.

address_mask

ubc_address_mask_t ubc_breakpoint_t::address_mask

Address mask.

Controls which of the low bits of ubc_breakpoint_t::address get excluded from the address comparison.

Note

This is used to create a breakpoint on a range of addresses.

[struct]

struct { ... } ubc_breakpoint_t::asid

Optional ASID settings.

These settings are used used when the MMU is enabled to distinguish between memory pages with the same virtual address.

break_before

bool ubc_breakpoint_t::break_before

Break before instruction execution.

Causes the breakpoint to be triggered just before the target instruction is actually executed.

Warning

Be careful when breaking before an instruction and returning "false" in your handler callback, as this can cause an infinite loop while the instruction gets repeatedly executed, repeatedly triggering your breakpoint handler.

[struct]

struct { ... } ubc_breakpoint_t::data

Optional operand data settings.

These settings allow for triggering an operand-access breakpoint on a particular value or range of values.

Warning

Only a single breakpoint utilizing data comparison settings may be active at a time, due to UBC channel limitations.

enabled

bool ubc_breakpoint_t::enabled

Enables data value comparisons.

Enables ASID value comparisons.

Must be enabled for data value comparisons to be used.

Must be enabled for ASID values to be used.

[struct]

struct { ... } ubc_breakpoint_t::instruction

Instruction access type settings.

Contains settings which are specific to instruction (or either) type accesses.

mask

uint32_t ubc_breakpoint_t::mask

Exclusion mask for data value comparison.

Controls which bits get masked off and excluded from operand-access value comparisons.

Note

This is used to break on a range of values.

next

struct ubc_breakpoint* ubc_breakpoint_t::next

Next breakpoint in the sequence.

Allows you to chain up to two breakpoint conditions together, creating a sequential breakpoint.

Warning

You can only ever have a single sequential breakpoint active at a time, with no other regular breakpoints active, as it requires both UBC channels to be in-use simultaneously.

Data comparison can only be used in the second breakpoint of a sequence.

When using a sequential breakpoint, the instructions triggering the first and second conditions must be { at least } 4 instructions away.

[struct]

struct { ... } ubc_breakpoint_t::operand

Operand access type settings.

Contains settings which are specific to operand (or either) type accesses.

rw

ubc_rw_t ubc_breakpoint_t::rw

Read/write condition.

Controls read/write condition for operand-access breakpoints

size

ubc_size_t ubc_breakpoint_t::size

Size condition.

Controls size condition for operand-access breakpoints

value [1/2]

uint32_t ubc_breakpoint_t::value

Data value for operand accesses.

Value to use for data comparisons with operand-access breakpoints.

Note

Since this field and its mask are only 32 bits wide, it will be compared to both the high and low 32-bits when using 64-bit operand sizes.

value [2/2]

uint8_t ubc_breakpoint_t::value

ASID value.

Sets the required ASID value for the virtual address given by ubc_breakpoint_t::address to match for a particular breakpoint.

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

• kernel/arch/dreamcast/include/dc/ubc.h