flight/libraries/PyMite/vm/frame.c

   1 /*
   2 # This file is Copyright 2003, 2006, 2007, 2009, 2010 Dean Hall.
   3 #
   4 # This file is part of the PyMite VM.
   5 # The PyMite VM is free software: you can redistribute it and/or modify
   6 # it under the terms of the GNU GENERAL PUBLIC LICENSE Version 2.
   7 #
   8 # The PyMite VM is distributed in the hope that it will be useful,
   9 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  11 # A copy of the GNU GENERAL PUBLIC LICENSE Version 2
  12 # is seen in the file COPYING in this directory.
  13 */
  14
  15
  16 #undef __FILE_ID__
  17 #define __FILE_ID__ 0x03
  18
  19
  20 /**
  21  * \file
  22  * \brief VM Frame
  23  *
  24  * VM frame operations.
  25  */
  26
  27
  28 #include "pm.h"
  29
  30
  31 PmReturn_t
  32 frame_new(pPmObj_t pfunc, pPmObj_t *r_pobj)
  33 {
  34     PmReturn_t retval = PM_RET_OK;
  35     int16_t fsize = 0;
  36     pPmCo_t pco = C_NULL;
  37     pPmFrame_t pframe = C_NULL;
  38     uint8_t *pchunk;
  39
  40     /* Get fxn's code obj */
  41     pco = ((pPmFunc_t)pfunc)->f_co;
  42
  43     /* TypeError if passed func's CO is not a true COB */
  44     if (OBJ_GET_TYPE(pco) != OBJ_TYPE_COB)
  45     {
  46         PM_RAISE(retval, PM_RET_EX_TYPE);
  47         return retval;
  48     }
  49
  50 #ifdef HAVE_GENERATORS
  51     /* #207: Initializing a Generator using CALL_FUNC needs extra stack slot */
  52     fsize = sizeof(PmFrame_t) + (pco->co_stacksize + pco->co_nlocals + 2) * sizeof(pPmObj_t);
  53 #elif defined(HAVE_CLASSES)
  54     /* #230: Calling a class's __init__() takes two extra spaces on the stack */
  55     fsize = sizeof(PmFrame_t) + (pco->co_stacksize + pco->co_nlocals + 1) * sizeof(pPmObj_t);
  56 #else
  57     fsize = sizeof(PmFrame_t) + (pco->co_stacksize + pco->co_nlocals - 1) * sizeof(pPmObj_t);
  58 #endif /* HAVE_CLASSES */
  59
  60 #ifdef HAVE_CLOSURES
  61     /* #256: Add support for closures */
  62     fsize = fsize + pco->co_nfreevars
  63             + ((pco->co_cellvars == C_NULL) ? 0 : pco->co_cellvars->length);
  64 #endif /* HAVE_CLOSURES */
  65
  66     /* Allocate a frame */
  67     retval = heap_getChunk(fsize, &pchunk);
  68     PM_RETURN_IF_ERROR(retval);
  69     pframe = (pPmFrame_t)pchunk;
  70
  71     /* Set frame fields */
  72     OBJ_SET_TYPE(pframe, OBJ_TYPE_FRM);
  73     pframe->fo_back = C_NULL;
  74     pframe->fo_func = (pPmFunc_t)pfunc;
  75     pframe->fo_memspace = pco->co_memspace;
  76
  77     /* Init instruction pointer and block stack */
  78     pframe->fo_ip = pco->co_codeaddr;
  79     pframe->fo_blockstack = C_NULL;
  80
  81     /* Get globals and attrs from the function object */
  82     pframe->fo_globals = ((pPmFunc_t)pfunc)->f_globals;
  83     pframe->fo_attrs = ((pPmFunc_t)pfunc)->f_attrs;
  84
  85 #ifndef HAVE_CLOSURES
  86     /* Empty stack points to one past locals */
  87     pframe->fo_sp = &(pframe->fo_locals[pco->co_nlocals]);
  88 #else
  89     /* #256: Add support for closures */
  90     pframe->fo_sp = &(pframe->fo_locals[pco->co_nlocals + pco->co_nfreevars
  91         + ((pco->co_cellvars == C_NULL) ? 0 : pco->co_cellvars->length)]);
  92 #endif /* HAVE_CLOSURES */
  93
  94     /* By default, this is a normal frame, not an import or __init__ one */
  95     pframe->fo_isImport = 0;
  96 #ifdef HAVE_CLASSES
  97     pframe->fo_isInit = 0;
  98 #endif
  99
 100     /* Clear the stack */
 101     sli_memset((unsigned char *)&(pframe->fo_locals), (char const)0,
 102                (unsigned int)fsize - sizeof(PmFrame_t));
 103
 104     /* Return ptr to frame */
 105     *r_pobj = (pPmObj_t)pframe;
 106     return retval;
 107 }