Diff: vm/pm.c

Revision:

0:65f1469d6bfb

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/vm/pm.c	Sat Mar 02 11:54:20 2013 +0000
@@ -0,0 +1,128 @@
+/*
+# This file is Copyright 2006 Dean Hall.
+# This file is part of the PyMite VM.
+# This file is licensed under the MIT License.
+# See the LICENSE file for details.
+*/
+
+
+#undef __FILE_ID__
+#define __FILE_ID__ 0x15
+
+
+/**
+ * \file
+ * \brief PyMite User API
+ *
+ * High-level functions to initialize and run PyMite
+ */
+
+
+#include "pm.h"
+
+
+/** Number of millisecond-ticks to pass before scheduler is run */
+#define PM_THREAD_TIMESLICE_MS  10
+
+
+/** Stores the timer millisecond-ticks since system start */
+volatile uint32_t pm_timerMsTicks = 0;
+
+/** Stores tick timestamp of last scheduler run */
+volatile uint32_t pm_lastRescheduleTimestamp = 0;
+
+
+PmReturn_t
+pm_init(uint8_t *heap_base, uint32_t heap_size,
+        PmMemSpace_t memspace, uint8_t const * const pusrimg)
+{
+    PmReturn_t retval;
+
+    /* Initialize the hardware platform */
+    retval = plat_init();
+    PM_RETURN_IF_ERROR(retval);
+
+    /* Initialize the heap and the globals */
+    retval = heap_init(heap_base, heap_size);
+    PM_RETURN_IF_ERROR(retval);
+
+    retval = global_init();
+    PM_RETURN_IF_ERROR(retval);
+
+    /* Load usr image info if given */
+    if (pusrimg != C_NULL)
+    {
+        retval = img_appendToPath(memspace, pusrimg);
+    }
+
+    return retval;
+}
+
+
+PmReturn_t
+pm_run(uint8_t const *modstr)
+{
+    PmReturn_t retval;
+    pPmObj_t pmod;
+    pPmObj_t pstring;
+    uint8_t const *pmodstr = modstr;
+    uint8_t objid1;
+    uint8_t objid2;
+
+    /* Import module from global struct */
+    retval = string_new(&pmodstr, &pstring);
+    PM_RETURN_IF_ERROR(retval);
+    heap_gcPushTempRoot(pstring, &objid1);
+    retval = mod_import(pstring, &pmod);
+    PM_RETURN_IF_ERROR(retval);
+
+    /* Load builtins into thread */
+    heap_gcPushTempRoot(pmod, &objid2);
+    retval = global_setBuiltins((pPmFunc_t)pmod);
+    PM_RETURN_IF_ERROR(retval);
+
+    /* Interpret the module's bcode */
+    retval = interp_addThread((pPmFunc_t)pmod);
+    PM_RETURN_IF_ERROR(retval);
+    heap_gcPopTempRoot(objid1);
+    retval = interpret(INTERP_RETURN_ON_NO_THREADS);
+
+    /*
+     * De-initialize the hardware platform.
+     * Ignore plat_deinit's retval so interpret's retval returns to caller.
+     */
+    plat_deinit();
+
+    return retval;
+}
+
+
+/* Warning: Can be called in interrupt context! */
+PmReturn_t
+pm_vmPeriodic(uint16_t usecsSinceLastCall)
+{
+    /*
+     * Add the full milliseconds to pm_timerMsTicks and store additional
+     * microseconds for the next run. Thus, usecsSinceLastCall must be
+     * less than 2^16-1000 so it will not overflow usecResidual.
+     */
+    static uint16_t usecResidual = 0;
+
+    C_ASSERT(usecsSinceLastCall < 64536);
+
+    usecResidual += usecsSinceLastCall;
+    while (usecResidual >= 1000)
+    {
+        usecResidual -= 1000;
+        pm_timerMsTicks++;
+    }
+
+    /* Check if enough time has passed for a scheduler run */
+    if ((pm_timerMsTicks - pm_lastRescheduleTimestamp)
+        >= PM_THREAD_TIMESLICE_MS)
+    {
+        interp_setRescheduleFlag((uint8_t)1);
+        pm_lastRescheduleTimestamp = pm_timerMsTicks;
+    }
+    return PM_RET_OK;
+}