Ross Thompson
5ebaeb5d90
Simplified the dcache to bus address generation.
2021-12-29 10:46:48 -06:00
Ross Thompson
15f1627a31
Fixed interrupt delay bug by reverting CommittedM changes.
2021-12-28 22:27:12 -06:00
Ross Thompson
29b3285c8e
Changed name of LSU's FetchCount to WordCount. This better reflex the dual usage as fetch and eviction counters.
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Fixed bug with the uncached memory operations. The periph tests still do not pass. They enter into what seems an intentional infinite loop. Then a uart interrupt jumps into an ISR but the ISR returns back to the loop.
2021-12-28 21:28:03 -06:00
Ross Thompson
7044277165
Changed the bus name between dcache and ebu.
2021-12-28 15:57:36 -06:00
Ross Thompson
c1789932a4
Added generate around virtual memory hardware in LSU.
2021-12-28 15:00:02 -06:00
Ross Thompson
44b63fc0ba
First cut at moving the dcache bus interface into the LSU.
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Regression test does not run and there is a lot of cleanup to do.
2021-12-27 18:12:59 -06:00
Ross Thompson
ae0cc085b4
Removed the fault state from the hptw. Now writing TLB faults into the I/DTLBs. This has two advantages.
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1: It simplifies the interactions between the caches and the hptw.
2: instruction page faults are fetched 3 times, caching them in the ITLB speeds up this process.
There are two downsides.
1: Pollute the TLBs with not very relavent translations
2: Have to compute the misalignment. This can be cached in the TLB which only costs 1 flip flop
for each TLB line.
2021-12-23 12:40:22 -06:00
Ross Thompson
82dd41a0fd
Rename of SelPTW to SelHPTW.
2021-12-19 22:24:07 -06:00
Ross Thompson
04d0b85f96
Fixed bug most of the bugs related to the dcache changes, but the mmu tests don't pass.
2021-12-19 16:12:31 -06:00
Ross Thompson
9adcf86a40
Modified the icache memory to read using the virtual (non physical) address in the PCNextF stage.
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This allows recovering from an ITLBMiss to be 1 cycle after and simplifies the hptw slightly.
2021-12-19 14:57:42 -06:00
Ross Thompson
0257c08641
Renamed MemAdrM to IEUAdrM. This will free the name MemAdrm for use in the DCache.
2021-12-19 14:00:30 -06:00
Ross Thompson
fdf493bd47
minro change. comments about needed changes in dcache.
2021-12-19 13:53:02 -06:00
David Harris
da1df17fbb
Do File cleanups
2021-12-17 17:45:26 -08:00
David Harris
24bb3f4baf
Added more pipeline stage suffixes to divider
2021-10-02 22:54:01 -04:00
Ross Thompson
99d675b872
Finished adding the d cache flush. Required ensuring the write data, address, and size are
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correct when transmitting to AHBLite interface.
2021-09-17 13:03:04 -05:00
Ross Thompson
d4398c23fb
Added states and all control and data path logic to support d cache flush. This is currently untested; however the existing regresss test passes.
2021-09-16 18:32:29 -05:00
Ross Thompson
eb7b5f1d63
Added invalidate to icache.
2021-09-16 16:15:54 -05:00
Ross Thompson
5bc90ef32f
Slight modification to wave file.
2021-09-08 10:40:46 -05:00
Ross Thompson
00f50184d8
Changed name of memory in icache.
2021-09-06 20:54:52 -05:00
Ross Thompson
5c2deab4e4
Partial multiway set associative icache.
2021-08-30 10:49:24 -05:00
Ross Thompson
de9e234ffa
Modified icache to no longer need StallF in the PCMux logic. Instead this is handled in the icachefsm.
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One downside is it increases the icache complexity. However it also fixes an untested bug. If a region
was uncacheable it would have been possible for the request to be made multiple times. Now that is
not possible. Additionally spills were oscillating between the spill hit states without this change.
The impact was 'benign' as the final spilled instruction always had the correct upper 16 bits.
2021-08-27 11:03:36 -05:00
Ross Thompson
cbb47956cb
Swapped out the icachemem for cacheway. cacheway is modified to optionally support dirty bits.
2021-08-26 15:43:02 -05:00
Ross Thompson
642efbb563
Converted the icache type from logic to state type.
2021-08-26 10:41:42 -05:00
Ross Thompson
d2b3b7345e
Moved dcache fsm to separate module.
2021-08-25 21:37:10 -05:00
Ross Thompson
7be0a73db1
Moved LRU and storage for the LRU into a single module. Also found a subtle bug with the update address used to write the cache's memory.
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This was correct for the LRU but incorrect for the data, tag, valid, and dirty storage.
2021-08-25 21:09:42 -05:00
Ross Thompson
c48556836b
Removed generate around the dcache memories.
2021-08-25 13:27:26 -05:00
Ross Thompson
4f3f26c5cb
Switched ExceptionM to dcache to be just exceptions.
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Added test bench logic to hold forces until the W stage is unstalled.
2021-08-13 15:53:50 -05:00
Ross Thompson
cd8a66353c
Patched up changes for wally-pipelined.do and wally-buildroot.do to support moved common testbench files.
2021-07-30 14:24:50 -05:00
Ross Thompson
32ec457e09
Removed the hardware page table walker fault state from the icache so that the icache will only unstall CPU for 1 cycle.
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In the dcache we added a register to save the load read data in the event an itlb miss occurs concurrently with
the load in the memory stage. Under this situation we need to record the load ReadDataM into a temporary register,
SavedReadDataM. At this time the CPU is stall; however the walker is going to change the address in the dcache
which destroys this data. When leaving the PTW_READY state via a walker instruction fault or ITLB write we select
this SavedReadDataM so that the CPU can capture it.
2021-07-22 19:42:19 -05:00
Ross Thompson
007812dbdc
Moved the ReadDataW register into the datapath.
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The StallW from the hazard unit controls this.
Previously it was in the dcache and controlled by both the HPTW and hazard unit.
This caused an issue when the CPU expected the data to stay constant while
stalled, but the HPTW was causing the data to be modified.
2021-07-22 14:52:03 -05:00
Ross Thompson
e907d57340
Tested all numbers of ways for dcache 1, 2, 4, and 8.
2021-07-22 10:38:07 -05:00
Ross Thompson
511c36fb1b
Improved address bus names and usages in the walker, dcache, and tlbs.
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Merge branch 'walkerEnhance' into main
2021-07-21 14:55:09 -05:00
Ross Thompson
39fc9278ba
Fixed remaining bugs in 2 way set associative dcache.
2021-07-21 10:35:23 -05:00
Ross Thompson
8d0a552b5b
Partially working 2 way set associative d cache.
2021-07-20 17:51:42 -05:00
Ross Thompson
2ee97efb9c
Fixed a complex bug in the dcache, where back to back loads would lose data on the load before a stall occurred. The solution was to modify the logic for SelAdrM in the dcache so that a stall would cause the SRAM to reread the address in the Memory stage rather than Execution stage. This also required updating the ReadDataWEn control so it is always enabled on ~StallW.
2021-07-19 12:32:16 -05:00
Ross Thompson
6ccbdc372d
Broken.
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Possible change to walker, dcache, tlb addressing.
Improves the naming of address signals.
But has a problem when the walker finishes the dcache does not get the correct
address on the cycle the DTLB is updated. This leads to incorrect index
selection in the dcache.
2021-07-19 10:33:27 -05:00
Ross Thompson
abce241f68
Also changed the shadow ram's dcache copy widths.
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Merge branch 'dcache' into main
2021-07-16 14:21:09 -05:00
Ross Thompson
bebc7cc5e3
Updated wave file.
2021-07-16 12:34:37 -05:00
Ross Thompson
d3715acf2d
Fixed walker fault interaction with dcache.
2021-07-16 12:22:13 -05:00
Ross Thompson
96aa106852
Found bug in the PMA such that invalid addresses were sent to the tim. Once addressing this issue the sv48 test fails early with a pma access fault.
2021-07-15 11:56:35 -05:00
Ross Thompson
5fb5ac3d5a
Updated wave file.
2021-07-15 11:04:49 -05:00
Ross Thompson
f234875779
dcache STATE_CPU_BUSY needs to assert CommittedM. This is required to ensure a completed memory operation is not bound to an interrupt. ie. MEPC should not be PCM when committed.
2021-07-14 23:08:07 -05:00
Ross Thompson
6163629204
Finally have the ptw correctly walking through the dcache to update the itlb.
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Still not working fully.
2021-07-14 22:26:07 -05:00
Ross Thompson
d3a1a2c90a
Fixed d cache not honoring StallW for uncache writes and reads.
2021-07-14 17:23:28 -05:00
Ross Thompson
771c7ff130
Routed CommittedM and PendingInterruptM through the lsu arb.
2021-07-14 16:18:09 -05:00
Ross Thompson
ef598d0e79
Implemented uncached reads.
2021-07-13 23:03:09 -05:00
Ross Thompson
278bbfbe3c
Partially working changes to support uncached memory access. Not sure what CommitedM is.
2021-07-13 17:24:59 -05:00
Ross Thompson
b780e471b4
Fixed interaction between icache stall and dcache. On hit dcache needs to enter a cpu busy state when the cpu is stalled.
2021-07-13 14:51:42 -05:00
Ross Thompson
51249a0e04
Fixed the fetch buffer accidental overwrite on eviction.
2021-07-13 14:21:29 -05:00
Ross Thompson
2034a6584f
Dcache AHB address generation was wrong. Needed to zero the offset.
2021-07-13 14:19:04 -05:00