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[/] [zipcpu/] [trunk/] [rtl/] [core/] - Rev 202

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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 2970d 07h /zipcpu/trunk/rtl/core/
91 Minor updates. dgisselq 3011d 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 3011d 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 3035d 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 3036d 22h /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 3036d 22h /zipcpu/trunk/rtl/core/
81 Trying to clean up ISE generated warnings. dgisselq 3036d 22h /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 3036d 22h /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 3042d 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 3048d 06h /zipcpu/trunk/rtl/core/

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