Commit Graph

41 Commits

Author SHA1 Message Date
Ross Thompson
14a69c1d06 Added the ability to exclude branch predictor. 2021-04-26 14:27:42 -05:00
Ross Thompson
9e40fb072c Merge branch 'tests' into icache-almost-working 2021-04-25 21:25:36 -05:00
Ross Thompson
d7fea1ba3c almost working icache. 2021-04-23 16:47:23 -05:00
Ross Thompson
c9bdaceddb Fixed icache for 32 bit.
Merge branch 'cache' into main
2021-04-22 16:45:29 -05:00
Ross Thompson
04eb302925 Yes. The hack to not repeat the d memory operation fixed this issue. 2021-04-22 15:22:56 -05:00
Ross Thompson
7c8d2e9b78 Partially working icache.
The current issue is a StallF is required to halt the icache from getting an updated PCF. However
if the dmemory is the reason for a stall it is possible for the icache stall to hold the d memory request continuously causing d memory to repeatedly read from memory.  This keeps StallF high and
the icache FSM is never allowed to complete.
2021-04-22 10:20:36 -05:00
Ross Thompson
50e893eec9 Fixed for the instruction spills. 2021-04-21 16:47:05 -05:00
Ross Thompson
269ea7997c major progress.
It's running the icache is imperas tests now.
Compressed does not work yet.
2021-04-21 08:39:54 -05:00
Ross Thompson
a861a37b72 Why was the linter messed up?
There are a number of combo loops which need fixing outside the icache.  They may be fixed in main.
We get to instruction address 50 now!
2021-04-20 22:06:12 -05:00
Ross Thompson
daa1ab9261 Progress on icache. Fixed some issues aligning the PC with instruction. Still broken. 2021-04-20 21:19:53 -05:00
Ross Thompson
649589ee2c Broken icache. Design is done. Time to debug. 2021-04-20 19:55:49 -05:00
Ross Thompson
75b97f1422 Created special test for driving the instruction spill error.
The extact problem occurs when a 4 byte instruction startles two cache blocks (or without a cache two ahbi words) and the code jumps to a cache block other than the next cache block. Consider the following sample of code.

0000000000000080 <test_spill>:
  80:	42a9                	li	t0,10
  82:	0001                	nop
  84:	0001                	nop
  86:	0001                	nop
  88:	02bd                	addi	t0,t0,15
  8a:	00628e33          	add	t3,t0,t1
  8e:	01ce8963          	beq	t4,t3,a0 <match>

0000000000000092 <failure>:
  92:	557d                	li	a0,-1
  94:	8082                	ret
  96:	00000013          	nop
  9a:	00000013          	nop
  9e:	0001                	nop

00000000000000a0 <match>:
  a0:	1ffd                	addi	t6,t6,-1
  a2:	fc0f9fe3          	bnez	t6,80 <test_spill>
  a6:	4501                	li	a0,0
  a8:	8082                	ret

Instructions 0x88, 0x8a and 0x8e are read incorrectly.  However once the branch predictor begins to correctly predict the beq at 0x8e the instrution at 0xa0 is loaded incorrectly as the 2 upper bytes of 0x8e and the two bytes of 0x92.  This amalgamation causes c.addi at 0xa0 to do something else and the loop never terminates.

The button of wavefile wave.do shows the exact problem in the 'icache'.
2021-04-08 15:05:08 -05:00
Ross Thompson
7f12c7af90 Switch to use RV64IC for the benchmarks.
Still not working correctly with the icache.

instr
addr   correct   got
2021-04-07 19:12:43 -05:00
Ross Thompson
d901cfc848 Merge branch 'icache_bp_bug' into tests
Not sure this merge is right.
2021-04-06 21:46:40 -05:00
Ross Thompson
0a20e33971 Steps to getting branch predictor benchmarks running. 2021-04-06 21:20:51 -05:00
Ross Thompson
a743acd1fd Partial fix to the integer divide stall issue. 2021-04-02 15:32:15 -05:00
Ross Thompson
1e83810450 Merge of main with the new icache and the branch predictor. I believe there is a bug in the icache with unaligned memory access. The second part of the access is incorrectly relying on the PCF being the address of the next two bytes of the instruction. However this is not always the case as the branch predictor can get the wrong target address. The icache needs to generate the +2 address internally. 2021-03-30 23:18:20 -05:00
ushakya22
ba01d57767 Merge branch 'main' of https://github.com/davidharrishmc/riscv-wally into main 2021-03-30 15:25:07 -04:00
ShreyaSanghai
da4086db79 Removed PCW and InstrW from ifu 2021-03-26 01:53:19 +05:30
Ross Thompson
cdb7d15709 Fixed bugs with the csr interacting with StallW. StallW is required to pervent updating a csr. Now have a working branch predictor and performance counters to track the number of commited branches and mispredictions. 2021-03-24 15:56:55 -05:00
Ross Thompson
a768c0406c Updated the function radix to have a new name FunctionName and it now pervents false transisions from the current function name when the PCD is flushed. 2021-03-24 13:03:43 -05:00
Ross Thompson
ace39940b4 Fixed RAS errors. Still some room for improvement with the BTB and RAS. 2021-03-23 23:00:44 -05:00
Ross Thompson
72d25d4443 Fixed a bunch of bugs with the RAS. 2021-03-23 21:49:16 -05:00
Ross Thompson
9d5c351340 fixed issue with BTB's valid bit not updating. There is still a problem is valid not ocurring in the correct clock cycle. 2021-03-23 20:06:45 -05:00
Ross Thompson
dee5d16850 fixed a whole bunch of bugs with the branch predictor. Still an issue with how PCNextF is not updated because the CPU is stalled. 2021-03-23 16:53:48 -05:00
Ross Thompson
4836e8fe2c Simulation definitely shows the branch predictor counters and branch predictor don't work. :( 2021-03-23 14:04:58 -05:00
Shreya Sanghai
dfc86539cc Merge branch 'gshare' into main
Conflicts:
	wally-pipelined/regression/wave.do
2021-03-18 17:25:48 -04:00
Ross Thompson
181a28e875 Fixed minor bug with the size of gshare. 2021-03-18 16:00:09 -05:00
Ross Thompson
31ad619a21 Added possibly working OSU test bench as a precursor to running a bp benchmark.
Fixed a few bugs with the function radix.
2021-03-17 11:06:32 -05:00
Ross Thompson
0637874cac Cleanup of the branch predictor flush and stall controls. 2021-03-12 14:57:53 -06:00
Ross Thompson
b1d1f3995c Improve version of the function radix which does not cause the wave file rendering to slow down. 2021-03-11 17:12:21 -06:00
Ross Thompson
149c9aa0f2 Added debug option to disable the function radix if not needed.
Function radix slows the simulation by 70 to 76 s (8.5%) for the rv64i tests.
2021-03-10 15:17:02 -06:00
Ross Thompson
4d7e926dbb I finally think I got the function radix debugger working across both 32 and 64 bit applications. 2021-03-10 14:43:44 -06:00
Ross Thompson
7b7cacbaf0 Finally I think I have the function radix mapping across all applications correctly. I still need to clean up the code a bit so it is easier to understand. 2021-03-10 11:00:51 -06:00
Ross Thompson
6191fcb1af Shreya and I found a bug with the exeuction of JAL and JALR instructions. The link was only set in the writeback stage. Once the branch predictor started correctly predicting JAL(R)s the ALU and forwarding logic need to have the PCLinkE at the execution stage in case an instruction in the next two clocks need the data. 2021-02-26 20:12:27 -06:00
Ross Thompson
c2cf3f9fb6 Updating the test bench to include a function radix. Not done. 2021-02-26 19:43:40 -06:00
Ross Thompson
c856003f73 RAS needs to be reset or preloaded. For now I just reset it.
Fixed bug with the instruction class.
Most tests now pass.  Only Wally-JAL and the compressed instruction tests fail.  Currently the bpred does not support compressed.  This will be in the next version.
2021-02-19 20:09:07 -06:00
Ross Thompson
597dd1e7e6 Added FlushF to hazard unit.
Fixed some typos with the names of signals in the branch predictor.  They were causing signals to be not set.  Note there is a modelsim flag which prevents it from compiling if a logic is undefined.
I will look this up and add it to the compiler.
2021-02-19 16:36:51 -06:00
Ross Thompson
06e975ac2f minor change to wave file. 2021-02-19 09:08:13 -06:00
Ross Thompson
7d6093b302 Hacked the sram memory models to reset their internal registers. This allows the simulation to run but is only temporary.
About 149307ns of simulation run.
2021-02-18 21:32:15 -06:00
Ross Thompson
8cbc9f7e51 Wrote a bash script to generate custom modelsim radix which maps instruction addresses into human readable lables.
Once combined with some simulation verilog this will display the current function in modelsim.
2021-02-17 22:20:28 -06:00