Intel IXC1100 用户手册

Intel

®

 IXP42X Product Line of Network Processors and IXC1100 Control Plane Processor

September 2006

DM

Order Number: 252480-006US

131

The download bit acts as a branch flag, signalling to the handler to continue with the 

download. This removes the need for a counter in the debug handler.

The overflow flag indicates that the debugger attempted to download the next word 

before the debugger read the previous word. 

More details on the Download bit, Overflow flag and high-speed download, in general, 

can be found in 

.

Following is example code showing how the Download bit and Overflow flag are used in 

the debug handler:

Prior to ending a debug session, the debugger should take the following actions:

1. Clear the DCSR (disable debug, exit Halt Mode, clear all vector traps, disable the 

trace buffer)

2. Turn off all breakpoints.
3. Invalidate the mini instruction cache.
4. Invalidate the main instruction cache.
5. Invalidate the BTB.

hs_write_word_loop:

hs_write_overflow:

bl

read_RX

@ read data word from host

@@ read TXRXCTRL into the CCs

mrc     p14, 0, r15, c14, c0, 0

bcc

hs_write_done

@ if D bit clear, download complete, exit loop.

beq

hs_write_overflow

@ if overflow detected, loop until host clears D 

bit

str

r0, [r6], #4

@ store only if there is no overflow.

b

hs_write_word_loop

@ get next data word

hs_write_done:

@@ after the loop, if the overflow flag was set, return error message to host

moveq

r0, #OVERFLOW_RESPONSE

beq

send_response

b

write_common_exit