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[/] [zipcpu/] [trunk/] [rtl/] - Rev 132

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64 Shuffled some comments into here from elsewhere. dgisselq 3079d 21h /zipcpu/trunk/rtl/
63 Simplified bus interactions, and added support for detecting illegal
instructions (i.e. bus errors) in the pipefetch routine.
dgisselq 3079d 22h /zipcpu/trunk/rtl/
62 Simplified the subtraction logic, so the carry bit no longer depends on
a separate 32-bit operation but becomes part of the subtract operation.
dgisselq 3079d 22h /zipcpu/trunk/rtl/
61 Simplified the bus delay logic. Depends upon the stall line being irrelevant
outside of a bus cycle.
dgisselq 3079d 22h /zipcpu/trunk/rtl/
56 Here's a bit of work in progress for getting the Zip CPU working on a XuLA2
board. Many changes include: the existence of a cpudefs.v file to control
what "options" are included in the ZipCPU build. This allows build control
to be separated from the project directory (one build for a XuLA2 board,
another for a Basys-3 development board). Other changes have made things
perhaps harder to read, but they get rid of warnings from XST.

A big change was the addition of the (* ram_style="distributed" *) comment
for the register set. This was necessary to keep XST from inferring a block
RAM and breaking the logic that was supposed to take place between a register
read and when it was used.
dgisselq 3090d 00h /zipcpu/trunk/rtl/
49 Final set of changes finishing the Dhrystone package. Dhrystone, as
implemented by hand in assembly, now works.
dgisselq 3099d 16h /zipcpu/trunk/rtl/
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 3099d 16h /zipcpu/trunk/rtl/
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 3102d 21h /zipcpu/trunk/rtl/
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 3112d 00h /zipcpu/trunk/rtl/
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 3137d 19h /zipcpu/trunk/rtl/

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