Rev |
Log message |
Author |
Age |
Path |
128 |
Cleaned up some comments. |
dgisselq |
3156d 07h |
/zipcpu/trunk/rtl/ |
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 |
3175d 08h |
/zipcpu/trunk/rtl/ |
115 |
A bug fix, applies to when there are more than 9 interrupt lines into the CPU. |
dgisselq |
3175d 15h |
/zipcpu/trunk/rtl/ |
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 |
3199d 16h |
/zipcpu/trunk/rtl/ |
91 |
Minor updates. |
dgisselq |
3240d 09h |
/zipcpu/trunk/rtl/ |
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 |
3240d 09h |
/zipcpu/trunk/rtl/ |
88 |
Eliminated some warnings. The div fixes were to simplify the logic, even though
the result is less readable ... |
dgisselq |
3264d 09h |
/zipcpu/trunk/rtl/ |
84 |
Minor updates. |
dgisselq |
3266d 07h |
/zipcpu/trunk/rtl/ |
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 |
3266d 07h |
/zipcpu/trunk/rtl/ |
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 |
3266d 07h |
/zipcpu/trunk/rtl/ |
81 |
Trying to clean up ISE generated warnings. |
dgisselq |
3266d 07h |
/zipcpu/trunk/rtl/ |
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 |
3266d 07h |
/zipcpu/trunk/rtl/ |
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 |
3271d 11h |
/zipcpu/trunk/rtl/ |
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 |
3277d 15h |
/zipcpu/trunk/rtl/ |
66 |
Adjusted the support for the DEBUG_SCOPE within these so that it can be
compiled in, or not, based upon an external build configuration file: cpudefs.v.
That allows me to make that file project specific, while the rest of the CPU
is shared among all projects. |
dgisselq |
3338d 15h |
/zipcpu/trunk/rtl/ |
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 |
3338d 15h |
/zipcpu/trunk/rtl/ |
64 |
Shuffled some comments into here from elsewhere. |
dgisselq |
3338d 15h |
/zipcpu/trunk/rtl/ |
63 |
Simplified bus interactions, and added support for detecting illegal
instructions (i.e. bus errors) in the pipefetch routine. |
dgisselq |
3338d 15h |
/zipcpu/trunk/rtl/ |
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 |
3338d 15h |
/zipcpu/trunk/rtl/ |
61 |
Simplified the bus delay logic. Depends upon the stall line being irrelevant
outside of a bus cycle. |
dgisselq |
3338d 15h |
/zipcpu/trunk/rtl/ |