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ISA: QNICE Instruction Set Architecture updated to version 1.6. The changes
are:- Interrupt system added.
- HALT instruction changed. The semantics opened the way for CONTROL
instructions such has HALT, RTI, INCRB and DECRB. The latter two mean that
instead of adding/subtracting something to the upper byte of the SR, one
can use these new commands. - SHL and SHR now modify Z and N condition flags.
The new ISA is documented in doc/intro/qnice_intro.pdf.
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PERFORMANCE: The new ISA leads to a speed increase of about 7% as documented
inq-tris_perf_test.asm
compared to the old ISA. The main reason is that
the new INCRB/DECRB only need two cycles compared to 4 cycles when switching
banks the old way. This leads to faster sub-routine calls. -
MMIO: Cleaned up the MMIO address space and by doing so, changed all the
locations of MMIO devices in sysdef.asm. This breaks binary compatibility
with all software from version 1.5 and older, and therefore all this
software needs to be reassembled and recompiled to run on version 1.6. -
CPU: Updates to reflect the new ISA. Added interrupt system. And a
comprehensive CPU test was added (test_programs/cpu_test.asm) and multiple
CPU bugs were fixed both in the emulator and in the hardware. -
MEGA65: Ported QNICE-FPGA to the MEGA65 (https://mega65.org/). This includes
adding HDMI and HyperRAM support for the MEGA65. -
TIMER INTERRUPT GENERATOR: Added. Is internally running on 100 kHz and
contains two independent counters (see sysdef.asm for details). -
INSTRUCTION COUNTER: Added. Counts all instructions executed by the CPU.
Can be used for performance testing as shown in
test_programs/q-tris_perf_test.asm and test_programs/mandel_perf_test.asm. -
UART: Added a 32 Byte FIFO to the UART. This was necessary because the
MEGA65 serial over JTAG does not support RTS/CTS and therefore we needed
more stability. Now RTS/CTS should be unnecessary in most cases. -
VHDL REFACTORINGS: The following system-wide refactorings have taken place
with the goal to improve the code quality and the FPGA performance:- register_file optimized to use LUTRAM instead of registers.
- replaced Tristate based inout DATA bus by separate DATA_IN and DATA_OUT.
- got rid of the large if/elsif/then section in mmio_mux and replaced by
more elegant direct logic assignments. - line endings in source files are now consistent with the unix scheme.
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MONITOR: Disassembler can now handle the new ISA.
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EMULATOR: Updated to reflect the new ISA.
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EMULATOR: Usability improved: At the "Q>" prompt the emulator now displays
the address from which the last instruction was read from. When an emulator
run is interrupted by CRTL/C (SIGINT) the statistics page now also lists
the last 16 addresses from which instructions were executed. -
EMULATOR: Made the WebAssembly target compatible with Emscripten 1.39.14
(and newer and it still works with 1.39.10 and some of the older versions,
but not with the versions in between). The background of this phenomenon is
explained here: emscripten-core/emscripten#10746 -
EMULATOR: Adjusted the standard emulation speed to 13.0 MIPS because this
is the average Q-TRIS performance. Peak performance observed so far is in
test_programs/mandel_perf_test.asm: 13.62 MIPS -
Q-TRIS: Adjusted (slowed down) to match the CPU's speed increase by 7%.
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TOOLCHAIN: Native assembler updated to reflect the ISA changes.
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TOOLCHAIN: C code emitter and standard C library and Monitor library
updated to reflect the MMIO changes. Standard C library recompiled to
use register bank switching instead of the stack in all function calls. -
TOOLCHAIN: qtransfer: Convenient mechanism for transferring software
(.out files) from the host computer to QNICE-FPGA. Details: doc/README.md -
TOOLCHAIN: Added support for Xilinx Vivado and made Vivado the main
toolchain for our project. ISE is still supported though. Structured all
hardware dependencies in the new folder 'hw' and added documentation
in 'hw/README.md'. -
TOOLCHAIN: Added Ubuntu Linux support, which means it should also run on
any other Debian based distribution. You might want to install xclip for
more convenience (.out copied to clipboard after assembler ran). -
QBIN: All sample applications have been rebuilt due to changes in the ISA
and the MMIO. A new download-link for the sample disk image is available:
http://sy2002x.de/hwdp/qnice_disk_v16.img -
DOCUMENTATION: Added:
- CONTRIBUTING.md
- doc/README.md
- doc/best-practices.md
- doc/how-to-release.md
- doc/int-device.md
- doc/mips.md
- hw/README.md
- vhdl/hw/MEGA65/README.md