frame.c

00001 /*
00002 # This file is Copyright 2003, 2006, 2007, 2009 Dean Hall.
00003 #
00004 # This file is part of the PyMite VM.
00005 # The PyMite VM is free software: you can redistribute it and/or modify
00006 # it under the terms of the GNU GENERAL PUBLIC LICENSE Version 2.
00007 #
00008 # The PyMite VM is distributed in the hope that it will be useful,
00009 # but WITHOUT ANY WARRANTY; without even the implied warranty of
00010 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
00011 # A copy of the GNU GENERAL PUBLIC LICENSE Version 2
00012 # is seen in the file COPYING in this directory.
00013 */
00014 
00015 
00016 #undef __FILE_ID__
00017 #define __FILE_ID__ 0x03
00018 
00019 
00020 /**
00021  * \file
00022  * \brief VM Frame
00023  *
00024  * VM frame operations.
00025  */
00026 
00027 
00028 #include "pm.h"
00029 
00030 
00031 PmReturn_t
00032 frame_new(pPmObj_t pfunc, pPmObj_t *r_pobj)
00033 {
00034     PmReturn_t retval = PM_RET_OK;
00035     int16_t fsize = 0;
00036     int8_t stacksz = (int8_t)0;
00037     int8_t nlocals = (int8_t)0;
00038     pPmCo_t pco = C_NULL;
00039     pPmFrame_t pframe = C_NULL;
00040     uint8_t const *paddr = C_NULL;
00041     uint8_t *pchunk;
00042 
00043     /* Get fxn's code obj */
00044     pco = ((pPmFunc_t)pfunc)->f_co;
00045 
00046     /* TypeError if passed func's CO is not a true COB */
00047     if (OBJ_GET_TYPE(pco) != OBJ_TYPE_COB)
00048     {
00049         PM_RAISE(retval, PM_RET_EX_TYPE);
00050         return retval;
00051     }
00052 
00053     /* Get sizes needed to calc frame size */
00054     if (pco->co_memspace == MEMSPACE_RAM)
00055     {
00056         paddr = (uint8_t *)((pPmCodeImgObj_t)pco->co_codeimgaddr)->val + CI_STACKSIZE_FIELD;
00057     }
00058     else
00059     {
00060         paddr = pco->co_codeimgaddr + CI_STACKSIZE_FIELD;
00061     }
00062     stacksz = mem_getByte(pco->co_memspace, &paddr);
00063 
00064     /* Now paddr points to CI_NLOCALS_FIELD */
00065     nlocals = mem_getByte(pco->co_memspace, &paddr);
00066 
00067 #ifdef HAVE_GENERATORS
00068     /* #207: Initializing a Generator using CALL_FUNC needs extra stack slot */
00069     fsize = sizeof(PmFrame_t) + (stacksz + nlocals + 2) * sizeof(pPmObj_t);
00070 #elif defined(HAVE_CLASSES)
00071     /* #230: Calling a class's __init__() takes two extra spaces on the stack */
00072     fsize = sizeof(PmFrame_t) + (stacksz + nlocals + 1) * sizeof(pPmObj_t);
00073 #else
00074     fsize = sizeof(PmFrame_t) + (stacksz + nlocals - 1) * sizeof(pPmObj_t);
00075 #endif /* HAVE_CLASSES */
00076 
00077 #ifdef HAVE_CLOSURES
00078     /* #256: Add support for closures */
00079     fsize = fsize + pco->co_nfreevars
00080             + ((pco->co_cellvars == C_NULL) ? 0 : pco->co_cellvars->length);
00081 #endif /* HAVE_CLOSURES */
00082 
00083     /* Allocate a frame */
00084     retval = heap_getChunk(fsize, &pchunk);
00085     PM_RETURN_IF_ERROR(retval);
00086     pframe = (pPmFrame_t)pchunk;
00087 
00088     /* Set frame fields */
00089     OBJ_SET_TYPE(pframe, OBJ_TYPE_FRM);
00090     pframe->fo_back = C_NULL;
00091     pframe->fo_func = (pPmFunc_t)pfunc;
00092     pframe->fo_memspace = pco->co_memspace;
00093 
00094     /* Init instruction pointer, line number and block stack */
00095     pframe->fo_ip = pco->co_codeaddr;
00096     pframe->fo_blockstack = C_NULL;
00097 
00098     /* Get globals and attrs from the function object */
00099     pframe->fo_globals = ((pPmFunc_t)pfunc)->f_globals;
00100     pframe->fo_attrs = ((pPmFunc_t)pfunc)->f_attrs;
00101 
00102 #ifndef HAVE_CLOSURES
00103     /* Empty stack points to one past locals */
00104     pframe->fo_sp = &(pframe->fo_locals[nlocals]);
00105 #else
00106     /* #256: Add support for closures */
00107     pframe->fo_sp = &(pframe->fo_locals[nlocals + pco->co_nfreevars
00108         + ((pco->co_cellvars == C_NULL) ? 0 : pco->co_cellvars->length)]);
00109 #endif /* HAVE_CLOSURES */
00110 
00111     /* By default, this is a normal frame, not an import or __init__ one */
00112     pframe->fo_isImport = 0;
00113 #ifdef HAVE_CLASSES
00114     pframe->fo_isInit = 0;
00115 #endif
00116 
00117     /* Clear the stack */
00118     sli_memset((unsigned char *)&(pframe->fo_locals), (char const)0,
00119                (unsigned int)fsize - sizeof(PmFrame_t));
00120 
00121     /* Return ptr to frame */
00122     *r_pobj = (pPmObj_t)pframe;
00123     return retval;
00124 }