Rev |
Log message |
Author |
Age |
Path |
130 |
Simplified the lock logic, and removed it when pipelining was not defined. This
also means the file is now dependent upon cpudefs.v. In another change, brev
was modified so as not to update the flags. This makes it useable with GCC
as a potential move or load immediate instruction. |
dgisselq |
3090d 22h |
/zipcpu/trunk/rtl/core/ |
129 |
Bug fix. Fixes some ugly race conditions that would cause code from the wrong
address to be executed. |
dgisselq |
3090d 22h |
/zipcpu/trunk/rtl/core/ |
118 |
Fixes two bugs: 1) in the early branching code within the instruction decoder.
This prevented the early branching from working when built with Xilinx's tools,
while the code worked with Verilator. 2) The CPU was not working with the
traditional cache and early branching disabled. These two bugs masked each
other. The replacement code is simpler. |
dgisselq |
3109d 23h |
/zipcpu/trunk/rtl/core/ |
105 |
Fixed some nasty early branching bugs. Adjusted the Makefile to declare that
cpudefs.h was automatically generated from cpudefs.v, and made sure that
zipbones included the cpudefs.v so it could get the DEBUG_SCOPE define.
In addition, the test.S was updated to test long jumps, the early branching
bug we found, and all three early branching instructions: ADD #x,PC, LOC(PC),PC,
and LDI #x,PC. |
dgisselq |
3134d 07h |
/zipcpu/trunk/rtl/core/ |
91 |
Minor updates. |
dgisselq |
3175d 00h |
/zipcpu/trunk/rtl/core/ |
90 |
Removed MOV x(PC),PC from the list of possible early branching instructions.
ADD X,PC and LDI X,PC are now the only recognized early branching instructions.
This was done to spare logic, although I don't think I spared more than a
LUT or two. |
dgisselq |
3175d 00h |
/zipcpu/trunk/rtl/core/ |
88 |
Eliminated some warnings. The div fixes were to simplify the logic, even though
the result is less readable ... |
dgisselq |
3199d 00h |
/zipcpu/trunk/rtl/core/ |
83 |
Added a flag to indicate whether an exception took place on the first
or second half of a VLIW instruction--will be zero in non-VLIW mode,
equivalent to the second half of the instruction having caused the
exception. (Expect these flags to be reordered some time in the future into
a less haphazard ordering ...)
Vastly simplified the pipeline logic, primarily for op_stall, but also touched
opA and opB. (Trying to fit within timing on Spartan 6 ...)
Changed division instruction to include a reset on clear_pipeline, to make
certain [BC $addr; DIV Rx,Ry ] works regardless of whether the condition is
true. |
dgisselq |
3200d 23h |
/zipcpu/trunk/rtl/core/ |
82 |
Found and (I hope) fixed a nasty bug that would send the prefetch into an
endless loop whenever you jumped to an instruction at the last location
in an unloaded cache line. |
dgisselq |
3200d 23h |
/zipcpu/trunk/rtl/core/ |
81 |
Trying to clean up ISE generated warnings. |
dgisselq |
3200d 23h |
/zipcpu/trunk/rtl/core/ |
80 |
Bug fix: declared the (combined) multiply to be signed again. Also
changed the name of the generate'd for block, to keep ISE from complaining. |
dgisselq |
3200d 23h |
/zipcpu/trunk/rtl/core/ |
71 |
This contains a bunch of bug fixes. (A lot ...) For example, the pipeline
stall code has also seriously changed, to fixed the pipeline memory load/op
stage conflict, while maintaining no-stall operation for operands that don't
need an offset. This had a cascading effect, however, so that the multiply
could no longer complete in a single cycle. Therefore, the timing on the
multiplies was slowed down to two cycles from a single cycle. (It's the
only two-cycle ALU operation ...) The illegal instruction code has also been
fixed, so that illegal instructions no longer stalls the prefetch bus. |
dgisselq |
3206d 02h |
/zipcpu/trunk/rtl/core/ |
69 |
This implements the "new Instruction Set" architecture for the Zip CPU. It's
a massive change set, that touches just about everything but probably not
enough of everything. Please see the spec.pdf for a description of this
new architecture. |
dgisselq |
3212d 06h |
/zipcpu/trunk/rtl/core/ |
65 |
Lots of logic simplifications to the core, in addition to better support for
illegal instruction detection and bus error detection. The biggest change
had to deal with pushing the debug write interface into the ALU write
processing path. This simplifies the logic of adjusting the PC and CC
registers primarily, but also any writes to other registers. It also delays
these register writes by a clock, but since the debug interface is already
ridiculously slow I doubt that matters any. |
dgisselq |
3273d 06h |
/zipcpu/trunk/rtl/core/ |
63 |
Simplified bus interactions, and added support for detecting illegal
instructions (i.e. bus errors) in the pipefetch routine. |
dgisselq |
3273d 07h |
/zipcpu/trunk/rtl/core/ |
62 |
Simplified the subtraction logic, so the carry bit no longer depends on
a separate 32-bit operation but becomes part of the subtract operation. |
dgisselq |
3273d 07h |
/zipcpu/trunk/rtl/core/ |
56 |
Here's a bit of work in progress for getting the Zip CPU working on a XuLA2
board. Many changes include: the existence of a cpudefs.v file to control
what "options" are included in the ZipCPU build. This allows build control
to be separated from the project directory (one build for a XuLA2 board,
another for a Basys-3 development board). Other changes have made things
perhaps harder to read, but they get rid of warnings from XST.
A big change was the addition of the (* ram_style="distributed" *) comment
for the register set. This was necessary to keep XST from inferring a block
RAM and breaking the logic that was supposed to take place between a register
read and when it was used. |
dgisselq |
3283d 09h |
/zipcpu/trunk/rtl/core/ |
49 |
Final set of changes finishing the Dhrystone package. Dhrystone, as
implemented by hand in assembly, now works. |
dgisselq |
3293d 01h |
/zipcpu/trunk/rtl/core/ |
48 |
Files added/updated to get Dhrystone benchmark to work. Several fixes
to the CPU in the process, 'cause it wasn't working. Stall-less ALU
ops now work better, to include grabbing the memory result as it comes out
of the memory unit and placing it straight into either ALU or memory unit
for the next instruction. |
dgisselq |
3293d 01h |
/zipcpu/trunk/rtl/core/ |
38 |
A couple of quick updates:
- The Zip CPU now supports pipelined memory access at one clock per
instruction (assuming all the instructions are in the cache)
- There is now a 'zipbones' module to build a Zip System without peripherals.
Any peripherals would then need to be external to the CPU.
- Some bug fixes.
Documentation changes coming shortly. |
dgisselq |
3296d 06h |
/zipcpu/trunk/rtl/core/ |