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[/] [zipcpu/] [trunk/] [rtl/] [core/] [idecode.v] - Rev 201

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201 RTL files for the 8-bit capable ZipCPU. dgisselq 1780d 20h /zipcpu/trunk/rtl/core/idecode.v
178 Rewrote the parameter controlled logic to be just that: perameter controller,
rather than depending upon generics. The result reduces our area by a couple
LUTs.
dgisselq 1955d 18h /zipcpu/trunk/rtl/core/idecode.v
160 Logic updates, and bug fix corrections to bring this in line with the current
XuLA2-LX25 SoC version. (i.e., the XuLA version was debugged and improved,
this update pushes those improvements to the mainline.)
dgisselq 2048d 14h /zipcpu/trunk/rtl/core/idecode.v
140 Minor changes, but fixes build of zippy_tb.cpp. dgisselq 2085d 02h /zipcpu/trunk/rtl/core/idecode.v
138 This updates the CPU multiply instruction into a set of three instructions.
MPY is a 32x32-bit multiply instruction, returning the low 32-bit result,
MPYUHI returns the upper 32-bits assuming the result was unsigned and MPYSHI
returns the upper 32-bits assuming the result was signed.
dgisselq 2087d 23h /zipcpu/trunk/rtl/core/idecode.v
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 2102d 14h /zipcpu/trunk/rtl/core/idecode.v
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 2121d 15h /zipcpu/trunk/rtl/core/idecode.v
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 2145d 23h /zipcpu/trunk/rtl/core/idecode.v
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 2186d 16h /zipcpu/trunk/rtl/core/idecode.v
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 2217d 18h /zipcpu/trunk/rtl/core/idecode.v
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 2223d 22h /zipcpu/trunk/rtl/core/idecode.v

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