TRCVISSCTLR

Trace ViewInst Start/Stop Control Register

Use this to select, or read, the Single Address Comparators for the ViewInst start/stop function.

Configuration

External register TRCVISSCTLR bits [31:0] are architecturally mapped to AArch64 System register TRCVISSCTLR[31:0].

This register is present only when FEAT_ETE is implemented, FEAT_TRC_EXT is implemented, and UInt(TRCIDR4.NUMACPAIRS) > 0. Otherwise, direct accesses to TRCVISSCTLR are RES0.

Attributes

TRCVISSCTLR is a 32-bit register.

Field descriptions

31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
STOP[15]	STOP[14]	STOP[13]	STOP[12]	STOP[11]	STOP[10]	STOP[9]	STOP[8]	STOP[7]	STOP[6]	STOP[5]	STOP[4]	STOP[3]	STOP[2]	STOP[1]	STOP[0]	START[15]	START[14]	START[13]	START[12]	START[11]	START[10]	START[9]	START[8]	START[7]	START[6]	START[5]	START[4]	START[3]	START[2]	START[1]	START[0]

STOP[<m>], bit [m+16], for m = 15 to 0:

Selects whether Single Address Comparator <m> is used with the ViewInst start/stop function for the purpose of stopping trace.

STOP[<m>]	Meaning
0b0	The Single Address Comparator <m> is not selected as a stop resource.
0b1	The Single Address Comparator <m> is selected as a stop resource.

The reset behavior of this field is:

On a Trace unit reset, this field resets to an architecturally UNKNOWN value.

Accessing this field has the following behavior:

When m >= UInt(TRCIDR4.NUMACPAIRS) * 2, access to this field is RES0 .
Otherwise, access to this field is RW.

START[<m>], bit [m], for m = 15 to 0:

Selects whether Single Address Comparator <m> is used with the ViewInst start/stop function for the purpose of starting trace.

START[<m>]	Meaning
0b0	The Single Address Comparator <m> is not selected as a start resource.
0b1	The Single Address Comparator <m> is selected as a start resource.

The reset behavior of this field is:

On a Trace unit reset, this field resets to an architecturally UNKNOWN value.

Accessing this field has the following behavior:

When m >= UInt(TRCIDR4.NUMACPAIRS) * 2, access to this field is RES0 .
Otherwise, access to this field is RW.

Accessing TRCVISSCTLR

Must be programmed if TRCIDR4.NUMACPAIRS > 0b0000.

For any 2 comparators selected for the ViewInst start/stop function, the comparator containing the lower address must be a lower numbered comparator.

If the trace unit is not in the Idle state it is CONSTRAINED UNPREDICTABLE whether writes to this register are ignored.

TRCVISSCTLR can be accessed through the external debug interface:

Component	Offset	Instance
ETE	0x088	TRCVISSCTLR

Accessible as follows:

When OSLockStatus(), or !AllowExternalTraceAccess(addrdesc), or !IsTraceCorePowered(), accesses to this register generate an error response.
Otherwise, accesses to this register are RW.

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