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37 Fixed some minor spelling errors. dgisselq 3139d 00h /zipcpu/trunk/
36 *Lots* of changes to increase processing speed and remove pipeline stalls.

Removed the useless flash cache, replacing it with a proper DMA controller.

"make test" in the main directory now runs a test program in Verilator and
reports on the results.
dgisselq 3139d 12h /zipcpu/trunk/
35 I updated the system diagram to reflect the new version that has a direct
memory access controller, rather than the (useless) manual cache.
dgisselq 3156d 03h /zipcpu/trunk/
34 Bunches of changes, although very little changed with the core itself.

Regarding the core, some bugs were fixed within zipcpu.v (the CPU part of the
core), so that the debugger can change the program counter. The debugger
can now halt the CPU and then view, examine, and modify registers to include
the program counter, although live changes to the CC register have not been
tested.

There was also a bug in the stall handling of the wishbone bus delay line. This
has now been fixed.

Moving outwards to the system, some parameters have been added to zipsystem
to make it more configurable for whatever environment you might wish to place
it within. Other minor clean ups have taken place, mostly to the internal
documentation.

Lots of changes, though, to the assembler. The big one is the implementation
of #define macros, C style. Several buggy macros were in sys.i. These have
been fixed. The Makefile has been adjusted so that the build of test.S, which
depends upon sys.i, is now properly dependent upon sys.i for make purposes.
Further, not only will zpp, the assembler preprocessor, handle #define macros,
it will also recursive #defines. The assembler expression evaluator has also
been updated to properly handle both operator precedence, as well as modulo
arithmetic.

The master system test file, test.S, found in the sw/zasm directory has been
updated to reflect these new capabilities. (I really need to move it to the
bench/asm directory, so you may expect that change sometime later.)
dgisselq 3165d 07h /zipcpu/trunk/
33 Finally finished a first draft of the full specification! dgisselq 3168d 06h /zipcpu/trunk/
32 Updated the document to match the most recent changes to the CPU. Specifically,
these include the re-instatement of the full SUB command with immediate offset,
and ... others I cannot remember.

The new document also describes what conditions create pipeline stalls,
together with how many cycles each stall condition will create.
dgisselq 3168d 13h /zipcpu/trunk/
31 README now comments on the relationship between the debugger and the
test bench. (They came from the same code at one time ...)
dgisselq 3168d 15h /zipcpu/trunk/
30 Here's a 20% increase in performance: We've gone from 0.44 clocks per
instruction up to 0.53 clocks per instruction on the test.S testset. The
cost? Oh, only about 300 slices.

Not bad.

The specification document will also soon be updated with a list of
conditions that create stalls, as eliminating stalls was how I managed to get
the performance up like I did.
dgisselq 3168d 15h /zipcpu/trunk/
29 Not sure what this file was, but it isn't a part of the project anymore. dgisselq 3168d 23h /zipcpu/trunk/
28 I got tired of running the make files across multiple directories, so I
built this makefile to coordinate building across each directory.
dgisselq 3169d 00h /zipcpu/trunk/

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