Add initial PVM test vectors

pvm/README.md

@@ -0,0 +1,33 @@
+# PVM Test Vectors, version 0.1
+
+## How to use this
+
+The [`programs`](./programs) directory contains `.json` files, each containing a single test.
+
+Here's an example of such a test:
+
+```
+{
+  "name": "inst_add",
+  "initial_regs": [0, 0, 0, 0, 0, 0, 0, 1, 2, 0, 0, 0, 0],
+  "code": [0, 0, 3, 8, 121, 8, 249],
+  "expected_status": "trap",
+  "expected_regs": [0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 0, 0, 0]
+}
+```
+
+* `name` -- a unique identifier for the test
+* `initial_regs` -- the initial value of each of the 13 registers; these need to be set *before* the test program is executed
+* `code` -- the code blob of the program to be executed as part of the test
+* `expected_status` -- the way the program is supposed to end; currently it can be one of the following:
+   - `"trap"` -- the execution ended with a trap (the `trap` instruction was executed, the execution went "out of bounds", an invalid jump was made, or an invalid instruction was executed)
+   - `"halt"` -- the execution finished gracefully (a dynamic jump to address `0xffff0000` was made)
+* `expected_regs` -- the expected values of each of the 13 registers *after* the test program is executed
+
+See [TESTCASES.md](./TESTCASES.md) for a human-readable index of all of the test cases.
+
+## Changelog
+
+### v0.1
+
+   * Initial test vectors.