Xilinx MicroBlaze Reference Manual page 297

wdc Write to Data Cache
wdc
wdc.flush
wdc.clear
wdc.clear.ea
wdc.ext.flush
wdc.ext.clear
1 0 0 1 0 0 0 0 0 0 0
0
6
Description
Write into the data cache tag to invalidate or flush a cache line. The mnemonic wdc.flush is used to set
the F bit, wdc.clear is used to set the T bit, wdc.clear.ea is used to set the T and EA bits, wdc.ext.flush
is used to set the E, F and T bits, and wdc.ext.clear is used to set the E and T bits.
When C_DCACHE_USE_WRITEBACK is set to 1:
• If the F bits is set, the instruction will flush and invalidate the cache line.
• Otherwise, the instruction will only invalidate the cache line and discard any data that has not
been written to memory.
• If the T bit is set, only a cache line with a matching address is invalidated:
If the EA bit is set register rA concatenated with rB is the extended address of the affected
°
cache line.
Otherwise, register rA added with rB is the address of the affected cache line.
°
The EA bit is only taken into account when the parameter C_ADDR_SIZE > 32.
°
• The E bit is not taken into account.
• The F and T bits cannot be used at the same time.
When C_DCACHE_USE_WRITEBACK is cleared to 0:
• If the E bit is not set, the instruction will invalidate the cache line. Register rA contains the
address of the affected cache line, and the register rB value is not used.
• Otherwise, MicroBlaze will request that the matching address in an external cache should be
invalidated or flushed, depending on the value of the F bit, and invalidate the internal affected
cache line. Register rA added with rB is the address in the external cache, and of the affected
cache line.
• The E bit is only taken into account when the parameter C_INTERCONNECT is set to 3 (ACE).
When MicroBlaze is configured to use an MMU (C_USE_MMU >= 1) the instruction is privileged. This
means that if the instruction is attempted in User Mode (MSR[UM] = 1) a Privileged Instruction
exception occurs.
MicroBlaze Processor Reference Guide
UG984 (v2018.2) June 21, 2018
rA,rB
rA,rB
rA,rB
rA,rB
rA,rB
rA,rB
rA
11
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Chapter 5: MicroBlaze Instruction Set Architecture
rB E 0 0 EA 1 1 F 0 1 T 0
16 21 31
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