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48 Files added/updated to get Dhrystone benchmark to work. Several fixes
to the CPU in the process, 'cause it wasn't working. Stall-less ALU
ops now work better, to include grabbing the memory result as it comes out
of the memory unit and placing it straight into either ALU or memory unit
for the next instruction.
dgisselq 2459d 23h /zipcpu/trunk/
47 Added some new graphics, includes the file for the Zip Bones system. dgisselq 2459d 23h /zipcpu/trunk/
46 A series of updates associated with getting Dhrystone to work. Includes
updates to getting multiple files to link/work together within the assembler,
as well as getting quoted quotations to work in the lexer, and better
include file support in the preprocessor.
dgisselq 2459d 23h /zipcpu/trunk/
45 Library routines for 32-bit multiply and divide, both signed and unsigned. dgisselq 2459d 23h /zipcpu/trunk/
44 ?? dgisselq 2459d 23h /zipcpu/trunk/
43 Minor edits to the C++ testbench. dgisselq 2459d 23h /zipcpu/trunk/
42 Oops -- forgot to add the stack. dgisselq 2459d 23h /zipcpu/trunk/
41 Assembly file for the Dhrystone benchmark added. dgisselq 2459d 23h /zipcpu/trunk/
40 Quick update, updates the assembly for the new version of the assembler. dgisselq 2459d 23h /zipcpu/trunk/
39 Here's the documentation update to support the pipelined read/writes of
the bus from the CPU, as well as the test file that proved they worked.
dgisselq 2463d 02h /zipcpu/trunk/
38 A couple of quick updates:

- The Zip CPU now supports pipelined memory access at one clock per
instruction (assuming all the instructions are in the cache)
- There is now a 'zipbones' module to build a Zip System without peripherals.
Any peripherals would then need to be external to the CPU.
- Some bug fixes.

Documentation changes coming shortly.
dgisselq 2463d 04h /zipcpu/trunk/
37 Fixed some minor spelling errors. dgisselq 2471d 19h /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 2472d 08h /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 2488d 22h /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 2498d 03h /zipcpu/trunk/
33 Finally finished a first draft of the full specification! dgisselq 2501d 01h /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 2501d 09h /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 2501d 10h /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 2501d 10h /zipcpu/trunk/
29 Not sure what this file was, but it isn't a part of the project anymore. dgisselq 2501d 19h /zipcpu/trunk/

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