From: Konstantinos Margaritis <konstantinos.margaritis@vectorcamp.gr>
Date: Tue, 20 Sep 2022 20:14:46 +0000 (+0000)
Subject: Initial PoC for calling pypowersim from within C code
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=8e68e31801751664725dbb4b2c43920640ccb71d;p=openpower-isa.git

Initial PoC for calling pypowersim from within C code
---

diff --git a/media/video/libvpx/pypowersim_wrapper_common.h b/media/video/libvpx/pypowersim_wrapper_common.h
new file mode 100644
index 00000000..3b442b5c
--- /dev/null
+++ b/media/video/libvpx/pypowersim_wrapper_common.h
@@ -0,0 +1,108 @@
+#include <Python.h>
+#include <stdint.h>
+#include <stdio.h>
+
+static const char* PLUGIN_NAME = "pypowersim";
+
+typedef struct pypowersim_state {
+    PyObject *name;
+    PyObject *plugin_module;
+    PyObject *binary;
+    PyObject *bigendian;
+    PyObject *prog;
+    PyObject *qemu_cosim;
+    PyObject *initial_regs;
+    PyObject *initial_sprs;
+    PyObject *svstate;
+    PyObject *mmu;
+    PyObject *initial_cr;
+    PyObject *initial_mem;
+    PyObject *initial_fprs;
+    PyObject *initial_pc;
+    PyObject *args;
+    PyObject *simulator;
+    PyObject *result_obj;
+} pypowersim_state_t;
+
+pypowersim_state_t *pypowersim_prepare(void) {
+    // Initialize Python C API
+    Py_Initialize();
+    // Add pypowersim directory to Python path
+    PyObject* sysPath = PySys_GetObject((char*)"path");
+    PyObject* curDir = PyUnicode_FromString("../../../src/openpower/decoder/isa/");
+    PyList_Append(sysPath, curDir);
+    Py_DECREF(curDir);
+
+    // Allocate memory for state
+    pypowersim_state_t *state = malloc(sizeof(pypowersim_state_t));
+    if (!state) {
+        printf("Error creating pypowersim_state object\n");
+	exit(1);
+    }
+    // Set plugin name and module
+    state->name = PyUnicode_FromString(PLUGIN_NAME);
+    state->plugin_module = PyImport_Import(state->name);
+    Py_DECREF(state->name);
+    if (!state->plugin_module) {
+        PyErr_Print();
+        printf("Error importing module\n");
+	exit(1);
+    }
+    // Set simulator object
+    state->simulator = PyObject_GetAttrString(state->plugin_module, "run_a_simulation");
+    Py_DECREF(state->plugin_module);
+    if (!state->simulator) {
+        PyErr_Print();
+        printf("Error retrieving 'run_a_simulation'\n");
+	exit(1);
+    }
+
+    // Little Endian for now
+    state->bigendian = Py_False;
+    state->prog = Py_None;
+    state->qemu_cosim = Py_False;
+    // Set and clear 128 GPRs
+    state->initial_regs = PyList_New(128);
+    for (int i=0; i < 128; i++) {
+       PyList_SetItem(state->initial_regs, i, PyLong_FromLong(0));
+    }
+    // Create SPRs to all bits set
+    state->initial_sprs= PyDict_New();
+    PyDict_SetItemString(state->initial_sprs, "LR",  PyLong_FromLong(0xffffff));
+    // Set empty SVSTATE
+    state->svstate = PyLong_FromLong(0);
+    // Set no MMU
+    state->mmu = Py_None;
+    // Set no initial CR
+    state->initial_cr = PyLong_FromLong(0);
+    // Set empty initial Memory
+    state->initial_mem = PyDict_New();
+    // Set and Clear 128 FPR
+    state->initial_fprs = PyList_New(128);
+    for (int i=0; i < 128; i++) {
+       PyList_SetItem(state->initial_fprs, i, PyLong_FromLong(0));
+    }
+    // Set initial Program Counter
+    state->initial_pc= PyLong_FromLong(0x0);
+
+    return state;
+}
+
+void pypowersim_prepareargs(pypowersim_state_t *state) {
+    // Set the tuple with the state objects
+    state->args = PyTuple_Pack(12, state->binary, state->bigendian, state->prog, state->qemu_cosim,
+		                  state->initial_regs, state->initial_sprs, state->svstate, state->mmu,
+				  state->initial_cr, state->initial_mem, state->initial_fprs, state->initial_pc );
+    if (!state->args) {
+        PyErr_Print();
+        Py_DECREF(state->simulator);
+        printf("Error building args tuple\n");
+	exit(1);
+    }
+}
+
+void pypowersim_finalize(void) {
+    // Finalize Python C API
+    Py_Finalize();
+}
+
diff --git a/media/video/libvpx/pypowersim_wrapper_example.c b/media/video/libvpx/pypowersim_wrapper_example.c
new file mode 100644
index 00000000..faa43920
--- /dev/null
+++ b/media/video/libvpx/pypowersim_wrapper_example.c
@@ -0,0 +1,65 @@
+#include <Python.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#include "pypowersim_wrapper_common.h"
+
+int test_function(int x) {
+    int result = 0;
+    for (int i=0; i < x; i++)
+        result += 2*i;
+    return result;
+}
+
+int test_function_wrapper(int x) {
+    // Create the pypowersim_state
+    pypowersim_state_t *state = pypowersim_prepare();
+
+    // Change the relevant elements, mandatory: body
+    //
+    state->binary = PyBytes_FromStringAndSize((const char *)&test_function, 1000);
+    // Set GPR #3 to the argument x
+    PyList_SetItem(state->initial_regs, 3, PyLong_FromLong(x));
+
+    // Prepare the args object
+    pypowersim_prepareargs(state);
+
+    // Call the function and get the resulting object
+    state->result_obj = PyObject_CallObject(state->simulator, state->args);
+    Py_DECREF(state->simulator);
+    Py_DECREF(state->args);
+    if (!state->result_obj) {
+        PyErr_Print();
+        printf("Error invoking 'run_a_simulation'\n");
+    }
+
+    // Get the GPRs from the result_obj
+    PyObject *final_regs = PyObject_GetAttrString(state->result_obj, "gpr");
+    if (!final_regs) {
+        PyErr_Print();
+        Py_DECREF(state->result_obj);
+        printf("Error getting final GPRs\n");
+    }
+
+    // GPR #3 holds the return value as an integer
+    PyObject *key = PyLong_FromLong(3);
+    PyObject *itm = PyDict_GetItem(final_regs, key);
+    PyObject *value = PyObject_GetAttrString(itm, "value");
+    uint64_t val = PyLong_AsLongLong(value);
+
+    Py_DECREF(state->result_obj);
+
+    // Return value
+    return val;
+}
+
+int main(int argc, char* argv[]) {
+    for (int i=0; i < 20; i++) {
+       int result = test_function_wrapper(i);
+       printf("i = %d, result = %d\n", i, result);
+    }
+    pypowersim_finalize();
+    return 0;
+}
+
+