diff options
| -rw-r--r-- | zpu/docs/zpu_arch.html | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/zpu/docs/zpu_arch.html b/zpu/docs/zpu_arch.html index 1346ecc..e09b915 100644 --- a/zpu/docs/zpu_arch.html +++ b/zpu/docs/zpu_arch.html @@ -5,6 +5,7 @@ <li> <a href="#started">Getting started</a> <li> <a href="#introduction">Introduction</a> <li> <a href="#instructionset">Instruction set</a> +<li> <a href="#implementing">Implementing your own ZPU</a> <li> <a href="#vectors">Jump vectors</a> <li> <a href="#memorymap">Memory map</a> <li> <a href="#interrupts">Interrupts</a> @@ -804,6 +805,34 @@ int address = pop();<br> </table> +<a name="implementing"/> +<h1>Implementing your own ZPU</h1> +One of the neat things about the ZPU is that the instruction set and architecture +is very small and it is easy to implement a ZPU from scratch or modify the +existing ZPU implementations. +<p> +Implementing a ZPU can be done without understanding the toolchain in +detail, i.e. using exclusively HDL skills and only a rudimentary +understanding of standard GCC/GDB usage is sufficient. +<p> +A few tips: +<ul> +<li>Run zpu_core.vhd or zpu_core_small.vhd and generate an instruction trace +from ModelSim or similar. To check that you own implementation is correctly +implemented, verify that the instruction trace for the new and old +ZPU implementations match. This gives you a simple way to do regression +tests as you develop your ZPU. +<li>To improve performance, you can add more instructions. The EMULATE instructions +are optional in HDL since they will be emulated in software if they are not +implemented in HDL. This allows you to run the ZPU executables unmodified +regardless of which EMULATE instructions you implement. +<li>Run the DMIPS test to measure your overall performance +<li>Run the histogram.perl script on the instruction trace to generate +histograms of the instructions. Profiling is essential to making +the right choices w.r.t. optimisation for your application. +</ul> + + <a name="vectors"/> <h1>Vectors</h1> <table border="1"> |
