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[/] [zipcpu/] [trunk/] [rtl/] [core/] - Rev 178

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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 3002d 22h /zipcpu/trunk/rtl/core
177 Fixed the illegal address logic to be more precise. dgisselq 3002d 22h /zipcpu/trunk/rtl/core
176 Switched from distributed to block RAM, and adjusted the logic to help
timing closure. The resulting core will build in designs up to 200MHz in
speed.
dgisselq 3002d 22h /zipcpu/trunk/rtl/core
175 Fixed the carry bit for logical shifts: it is the last bit shifted out of the
register. 0x80000000>>32 yields a 0 with carry set. Anything logically
shifted by a number greater than thirty two clears carry and register.
dgisselq 3002d 22h /zipcpu/trunk/rtl/core
174 Simplified the divide to improve timing performance. dgisselq 3002d 22h /zipcpu/trunk/rtl/core
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 3095d 18h /zipcpu/trunk/rtl/core
145 This fixes the pipelined memory problem that was introduced a while back to
fix ... pipelined memory conflicts. This appears to maintain the success
of the fix, while recovering the pipeline memory performance that was had
before.
dgisselq 3128d 17h /zipcpu/trunk/rtl/core
140 Minor changes, but fixes build of zippy_tb.cpp. dgisselq 3132d 06h /zipcpu/trunk/rtl/core
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 3135d 03h /zipcpu/trunk/rtl/core
133 Changes preceding an instruction set update, which will change the multiply
operation from a 16x16 bit multiply to three types of 32x32-bit multiplies.
dgisselq 3149d 18h /zipcpu/trunk/rtl/core
132 Lots of minor bug fixes. dgisselq 3149d 18h /zipcpu/trunk/rtl/core
131 Fixed a variable use before declaration error. dgisselq 3149d 18h /zipcpu/trunk/rtl/core
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 3149d 18h /zipcpu/trunk/rtl/core
129 Bug fix. Fixes some ugly race conditions that would cause code from the wrong
address to be executed.
dgisselq 3149d 18h /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 3168d 19h /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 3193d 03h /zipcpu/trunk/rtl/core
91 Minor updates. dgisselq 3233d 20h /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 3233d 20h /zipcpu/trunk/rtl/core
88 Eliminated some warnings. The div fixes were to simplify the logic, even though
the result is less readable ...
dgisselq 3257d 20h /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 3259d 18h /zipcpu/trunk/rtl/core

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