Trace Unit Registers
SC140 DSP Core Reference Manual
4-55
4.9.2 Trace Buffer Read Pointer Register (TB_RD)
TB_RD is a 16-bit register that points to the location in the RAM buffer from which the next value is read.
The register is reset when the trace buffer is enabled.
TEN
Bit 4
Trace Buffer Enable Mode
— Enables
the trace buffer. The TEN bit can be set
or cleared directly. It can also be set
when TB is enabled by the ES_ETB. It is
cleared when disabled by the ES_DTB.
0 = Trace buffer is disabled.
1 = Trace buffer is always operational.
TMARK
Bit 3
Trace Mark Instruction Mode
—
Enables the trace of MARK instruction
execution.
0 = MARK instruction is not traced.
1 = PC of MARK instruction is traced.
TEXEC
Bit 2
Trace Issue of Execution Sets Enable
Mode
— Enables tracing the addresses
of every issued execution set.
0 = Only specific addresses are written to the TB as
controlled by the other mode bits.
1 = Only one entry can be written to the TB, the first
address of each execution set. All other mode bits
should be cleared.
TINT
Bit 1
Trace Interrupts Enable Mode
— Used
to enable tracing the addresses of
interrupt vectors. When the bit is set,
each service of an interrupt puts the
address of the last executed
execution set (before the interrupt) into
the trace buffer as well as the address of
the interrupt vector. If the bit is cleared,
addresses of interrupt vectors will not be
put into the trace buffer.
1 = Four entries per cycle can be written to the TB:
Source address
Destination address
Two additional words: the event counter register value
if TCOUNT is set, and/or the extension counter
register value if TCNTEXT is set. When TCOUNT and
TCNTEXT are both set, the corresponding values are
written to the TB at different cycles.
TCHOF
Bit 0
Trace Addresses of Change-of-Flow
Instructions Enable Mode
— Used to
enable the tracing of addresses for
execution sets containing
change-of-flow instructions. When the
bit is set, every execution of an
execution set containing change-of-flow
instructions (even if the change-of-flow
instruction is executed together with
other instructions in the execution set)
puts into the trace buffer the address of
that execution set (the address of the
first instruction in the execution set) and
the target address of the change-of-flow
instruction.
If the bit is cleared, the addresses of the
execution sets containing
change-of-flow instructions are not put
into the trace buffer unless all
execution sets are enabled to be traced.
1 = Three entries per cycle can be written to the TB:
Source address
Destination address
One additional word: the event counter register value
(if TCOUNT is set), or the extension counter register
value (if TCNTEXT is set).
Table 4-18. TB_CTRL Description (Continued)
Name
Description
Settings