
11-8
G2 PowerPC Core Reference Manual
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MOTOROLA
Synchronization Requirements
This matches when the instruction’s effective address < IABR_ADDR OR the instruction’s
effective address
≤
IABR2_ADDR.
The breakpoint match can be observed externally through watchpoint signals. When
DCBR[SIG_TYPE] or ICBR[SIG_TYPE] is cleared for an OR signal type, the watchpoint
signals—core_iabr, core_iabr2, core_dabr, and core_dabr2—reflect their respective
breakpoints. When DCBR[SIG_TYPE] or ICBR[SIG_TYPE] is set for an AND signal
type, the watchpoint signals core_iabr2 and core_dabr2 are asserted when the AND
condition is met.The watchpoint signal has to asserted for at least one bus clock cycle. For
more details, see Section 2.1.2.14.1, “Instruction Address Breakpoint Control Registers
(IBCR)—G2_LE Only,” and Section 2.1.2.15.1, “Data Address Breakpoint Control
Registers (DBCR)—G2_LE-Only.”
11.6 Synchronization Requirements
An
isync
instruction must follow the setting of the
mtspr
of the breakpoint related registers,
MSR, HID0, IABR, IABR2, DABR, DABR2, IBCR, and DBCR to ensure that the
breakpoint condition is set. IBCR and DBCR should be set before enabling the breakpoint.
The breakpoint should be cleared before changing bits in the IBCR and DCBR. For more
details, see Section 5.5.16, “Instruction Address Breakpoint Exception (0x01300).”
An unrecoverable state occurs at anytime if one of the register values of IABR, IABR2,
DABR, and DABR2 are set to an exception vector. The IABR or IABR2 values must not
be set to match within the instruction address breakpoint exception handler. The DABR or
DABR2 values must not be set to the DSI exception handler. Failure to prohibit a
breakpoint within the instruction address breakpoint exception or DSI handler may result
an unrecoverable and indeterminate processor core state.
If an IABR match and DABR match occur on the same instruction, the instruction address
breakpoint exception is taken before the DSI exception.
If an IABR match occurs on a branch instruction, the instruction address breakpoint
exception is set to the effective address of the branch instruction.
Table 11-6. Address Matching for Outside Address Range
Signal
Condition
Signal
Condition
IABR[CEA]
IABR_ADDR
IABR2[CEA]
IABR2_ADDR
IABR[BE]
1
IABR2[BE]
1
IBCR[CNT]
0
—
—
IBCR[SIG_TYPE]
OR
—
—
IBCR[CMP1]
<
IBCR[CMP2]
>
F
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