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55 A test was added to double check whether carry following right shifts worked.
This was a necessary part of getting two cycle linear feedback shift register
operations working for a memory test on a XuLA2 board. With this, I can now
verify that such feedback registers work for pseudorandom number purposes.
dgisselq 3105d 20h /
54 This builds on the support for backslash character escapes in both single
and multicharacter expressions. Backslash character escapes are now
possible with quotations and backslashes, and the same code to interpret
the escapes is applied to both single and multicharacter sequences.
dgisselq 3105d 20h /
53 Updated the #include/#define directives to work properly for nested includes.
(They were supposed to work properly for nested includes before ... and didn't)
This fixes those bugs.
dgisselq 3105d 20h /
52 Added the capability to "see" character's encoded within a binary file,
by printing the character value(s) of each opcode (if they are printable)
on each line.
dgisselq 3105d 20h /
51 Added the capability to look at binary files and 'see' characters as they
are encoded in memory.
dgisselq 3105d 20h /
50 Dhrystone benchmark updates--added the copyright notice. (Oops!) dgisselq 3115d 11h /
49 Final set of changes finishing the Dhrystone package. Dhrystone, as
implemented by hand in assembly, now works.
dgisselq 3115d 11h /
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 3115d 11h /
47 Added some new graphics, includes the file for the Zip Bones system. dgisselq 3115d 12h /
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 3115d 12h /
45 Library routines for 32-bit multiply and divide, both signed and unsigned. dgisselq 3115d 12h /
44 ?? dgisselq 3115d 12h /
43 Minor edits to the C++ testbench. dgisselq 3115d 12h /
42 Oops -- forgot to add the stack. dgisselq 3115d 12h /
41 Assembly file for the Dhrystone benchmark added. dgisselq 3115d 12h /
40 Quick update, updates the assembly for the new version of the assembler. dgisselq 3115d 12h /
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 3118d 14h /
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 3118d 17h /
37 Fixed some minor spelling errors. dgisselq 3127d 07h /
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 3127d 20h /
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 3144d 11h /
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 3153d 15h /
33 Finally finished a first draft of the full specification! dgisselq 3156d 13h /
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 3156d 21h /
31 README now comments on the relationship between the debugger and the
test bench. (They came from the same code at one time ...)
dgisselq 3156d 22h /
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 3156d 22h /
29 Not sure what this file was, but it isn't a part of the project anymore. dgisselq 3157d 07h /
28 I got tired of running the make files across multiple directories, so I
built this makefile to coordinate building across each directory.
dgisselq 3157d 08h /
27 The big change to the test bench code in this directory is the support for
non-interactive operation. The test bench will now run in non-interactive
mode until either the CPU HALT's or executes a BUSY instruction. A 'HALT'
is deemed a test success, whereas a BUSY is deemed a test failure.

A usage() statement now informs the user what commands are available while
running the test bench interactively. (It looks a lot like the debugger looks
like, should you manage to get that up and running.)

The make file now also supports interactive and non-interactive testing via
the 'make itest' and 'make test' targets respectively.
dgisselq 3157d 08h /
26 Added signed and unsigned multiply opcodes to the assembler.

An opcode was added for a 'negate' instruction. This is a derived instruction
that turns into two instructions. Neg RX becomes an XOR -1,Rx followed by an
Add 1,Rx command. (Move 1+Rx,Rx would've stalled the bus by one cycle.)

Instructions now keep track of the source linenumber (but not yet filename)
where they were issued. That way, upon an error in linking at the end, the
instruction can be referenced by the proper line number. (Filenames are still
not implemented, hence include files may reference the line number of the
include file with no proper indication of that ... yet).

The OBJFILE intrface now supports a clos() function. This allows the
assembler to close and delete the object file for those cases where the
preprocessor encounters an error.

The master test file, sw/test.S, was adjuted as follows: many of the tests
within it can be separated by #ifdef lines. Hence, if you only wish to test
whether or not CARRY works, undefine all of the other ifdefs but leave the
CARRY_TEST defined. (PUSH_TEST, a test of the PUSH(RX,SP) macro, still doesn't
work because the assembler still doesn't implement macros. This is still a
coming feature.)

The master test file now has tests for the break function, as well as for the
new trap CC bit and the new multiply signed and unsigned instructions in the
ALU.

Many error conditions were added to the assembler preprocessor. Now, if an
EOF is encountered in anything but the INITIAL state (not within a macro),
an error will be created. Likewise, any unrecognized preprocessor directive
will create an error.

The lexical analyzer now supports character values, such as 'a' or '\n' using
a C-type syntax. (Tri-graphs are not supported.) It also supports such
extended syntax as '$GPG'. (Hmm ... wonder why I needed that?)

The lexical analyzer now recognizes and properly supports #line preprocessor
output statements. Theselines are then used to track what source line errors
occurr at.

Operand precedence has been adjusted, so the assembler should be able to
properly handle things like 5+3*8 and get the same number answer as 3*8+5.
(This has been implemented, although not thoroughly tested.)

Upon completion of any preprocessing file, the assembler now checks the status
of the preprocessor as returned by its exit code. Anything other than a zero
status will cause the assembler to delete the resulting object code file it is
building and exit with an error.

The assembler also supports the '-d' command line flag to turn on debugging in
the yacc processor (setting yydebug). It'll produce a lot of debugging output,
but it just might help to figure out what 'syntax error' is actually taking
place.
dgisselq 3157d 08h /

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