interp.h

00001 /*
00002 # This file is Copyright 2002 Dean Hall.
00003 # This file is part of the PyMite VM.
00004 # This file is licensed under the MIT License.
00005 # See the LICENSE file for details.
00006 */
00007 
00008 
00009 #ifndef __INTERP_H__
00010 #define __INTERP_H__
00011 
00012 
00013 /**
00014  * \file
00015  * \brief VM Interpreter
00016  *
00017  * VM interpreter header.
00018  */
00019 
00020 
00021 #include "thread.h"
00022 
00023 
00024 #define INTERP_LOOP_FOREVER          0
00025 #define INTERP_RETURN_ON_NO_THREADS  1
00026 
00027 
00028 /** Frame pointer ; currently for single thread */
00029 #define PM_FP (gVmGlobal.pthread->pframe)
00030 /** Instruction pointer */
00031 #define PM_IP (PM_FP->fo_ip)
00032 /** Argument stack pointer */
00033 #define PM_SP (PM_FP->fo_sp)
00034 
00035 /** top of stack */
00036 #define TOS             (*(PM_SP - 1))
00037 /** one under TOS */
00038 #define TOS1            (*(PM_SP - 2))
00039 /** two under TOS */
00040 #define TOS2            (*(PM_SP - 3))
00041 /** three under TOS */
00042 #define TOS3            (*(PM_SP - 4))
00043 /** index into stack; 0 is top, 1 is next */
00044 #define STACK(n)        (*(PM_SP - ((n) + 1)))
00045 /** pops an obj from the stack */
00046 #define PM_POP()        (*(--PM_SP))
00047 /** pushes an obj on the stack */
00048 #define PM_PUSH(pobj)   (*(PM_SP++) = (pobj))
00049 /** gets the argument (S16) from the instruction stream */
00050 #define GET_ARG()       mem_getWord(PM_FP->fo_memspace, &PM_IP)
00051 
00052 /** pushes an obj in the only stack slot of the native frame */
00053 #define NATIVE_SET_TOS(pobj) (gVmGlobal.nativeframe.nf_stack = \
00054                         (pobj))
00055 /** gets the nth local var from the native frame locals */
00056 #define NATIVE_GET_LOCAL(n) (gVmGlobal.nativeframe.nf_locals[n])
00057 /** gets a pointer to the frame that called this native fxn */
00058 #define NATIVE_GET_PFRAME()   (*ppframe)
00059 /** gets the number of args passed to the native fxn */
00060 #define NATIVE_GET_NUM_ARGS() (gVmGlobal.nativeframe.nf_numlocals)
00061 
00062 
00063 /**
00064  * COMPARE_OP enum.
00065  * Used by the COMPARE_OP bytecode to determine
00066  * which type of compare to perform.
00067  * Must match those defined in Python.
00068  */
00069 typedef enum PmCompare_e
00070 {
00071     COMP_LT = 0,            /**< less than */
00072     COMP_LE,                /**< less than or equal */
00073     COMP_EQ,                /**< equal */
00074     COMP_NE,                /**< not equal */
00075     COMP_GT,                /**< greater than */
00076     COMP_GE,                /**< greater than or equal */
00077     COMP_IN,                /**< is in */
00078     COMP_NOT_IN,            /**< is not in */
00079     COMP_IS,                /**< is */
00080     COMP_IS_NOT,            /**< is not */
00081     COMP_EXN_MATCH          /**< do exceptions match */
00082 } PmCompare_t, *pPmCompare_t;
00083 
00084 /**
00085  * Byte code enumeration
00086  */
00087 typedef enum PmBcode_e
00088 {
00089 #ifdef HAVE_PYTHON27
00090     STOP_CODE=0, /* 0x00 */
00091     POP_TOP=1, /* 0x01 */
00092     ROT_TWO=2, /* 0x02 */
00093     ROT_THREE=3, /* 0x03 */
00094     DUP_TOP=4, /* 0x04 */
00095     ROT_FOUR=5, /* 0x05 */
00096     UNUSED_06=6,
00097     UNUSED_07=7,
00098     UNUSED_08=8,
00099     NOP=9, /* 0x09 */
00100     UNARY_POSITIVE=10, /* 0x0a */
00101     UNARY_NEGATIVE=11, /* 0x0b */
00102     UNARY_NOT=12, /* 0x0c */
00103     UNARY_CONVERT=13, /* 0x0d */
00104     UNUSED_0E=14,
00105     UNARY_INVERT=15, /* 0x0f */
00106     UNUSED_10=16,
00107     UNUSED_11=17,
00108     UNUSED_12=18,
00109     BINARY_POWER=19, /* 0x13 */
00110     BINARY_MULTIPLY=20, /* 0x14 */
00111     BINARY_DIVIDE=21, /* 0x15 */
00112     BINARY_MODULO=22, /* 0x16 */
00113     BINARY_ADD=23, /* 0x17 */
00114     BINARY_SUBTRACT=24, /* 0x18 */
00115     BINARY_SUBSCR=25, /* 0x19 */
00116     BINARY_FLOOR_DIVIDE=26, /* 0x1a */
00117     BINARY_TRUE_DIVIDE=27, /* 0x1b */
00118     INPLACE_FLOOR_DIVIDE=28, /* 0x1c */
00119     INPLACE_TRUE_DIVIDE=29, /* 0x1d */
00120     SLICE_0=30, /* 0x1e */
00121     SLICE_1=31, /* 0x1f */
00122     SLICE_2=32, /* 0x20 */
00123     SLICE_3=33, /* 0x21 */
00124     UNUSED_22=34,
00125     UNUSED_23=35,
00126     UNUSED_24=36,
00127     UNUSED_25=37,
00128     UNUSED_26=38,
00129     UNUSED_27=39,
00130     STORE_SLICE_0=40, /* 0x28 */
00131     STORE_SLICE_1=41, /* 0x29 */
00132     STORE_SLICE_2=42, /* 0x2a */
00133     STORE_SLICE_3=43, /* 0x2b */
00134     UNUSED_2C=44,
00135     UNUSED_2D=45,
00136     UNUSED_2E=46,
00137     UNUSED_2F=47,
00138     UNUSED_30=48,
00139     UNUSED_31=49,
00140     DELETE_SLICE_0=50, /* 0x32 */
00141     DELETE_SLICE_1=51, /* 0x33 */
00142     DELETE_SLICE_2=52, /* 0x34 */
00143     DELETE_SLICE_3=53, /* 0x35 */
00144     STORE_MAP=54, /* 0x36 */
00145     INPLACE_ADD=55, /* 0x37 */
00146     INPLACE_SUBTRACT=56, /* 0x38 */
00147     INPLACE_MULTIPLY=57, /* 0x39 */
00148     INPLACE_DIVIDE=58, /* 0x3a */
00149     INPLACE_MODULO=59, /* 0x3b */
00150     STORE_SUBSCR=60, /* 0x3c */
00151     DELETE_SUBSCR=61, /* 0x3d */
00152     BINARY_LSHIFT=62, /* 0x3e */
00153     BINARY_RSHIFT=63, /* 0x3f */
00154     BINARY_AND=64, /* 0x40 */
00155     BINARY_XOR=65, /* 0x41 */
00156     BINARY_OR=66, /* 0x42 */
00157     INPLACE_POWER=67, /* 0x43 */
00158     GET_ITER=68, /* 0x44 */
00159     UNUSED_45=69,
00160     PRINT_EXPR=70, /* 0x46 */
00161     PRINT_ITEM=71, /* 0x47 */
00162     PRINT_NEWLINE=72, /* 0x48 */
00163     PRINT_ITEM_TO=73, /* 0x49 */
00164     PRINT_NEWLINE_TO=74, /* 0x4a */
00165     INPLACE_LSHIFT=75, /* 0x4b */
00166     INPLACE_RSHIFT=76, /* 0x4c */
00167     INPLACE_AND=77, /* 0x4d */
00168     INPLACE_XOR=78, /* 0x4e */
00169     INPLACE_OR=79, /* 0x4f */
00170     BREAK_LOOP=80, /* 0x50 */
00171     WITH_CLEANUP=81, /* 0x51 */
00172     LOAD_LOCALS=82, /* 0x52 */
00173     RETURN_VALUE=83, /* 0x53 */
00174     IMPORT_STAR=84, /* 0x54 */
00175     EXEC_STMT=85, /* 0x55 */
00176     YIELD_VALUE=86, /* 0x56 */
00177     POP_BLOCK=87, /* 0x57 */
00178     END_FINALLY=88, /* 0x58 */
00179     BUILD_CLASS=89, /* 0x59 */
00180     
00181     /* Opcodes from here have an argument */
00182     HAVE_ARGUMENT=90, /* 0x5a */
00183     STORE_NAME=90, /* 0x5a */
00184     DELETE_NAME=91, /* 0x5b */
00185     UNPACK_SEQUENCE=92, /* 0x5c */
00186     FOR_ITER=93, /* 0x5d */
00187     LIST_APPEND=94, /* 0x5e */
00188     STORE_ATTR=95, /* 0x5f */
00189     DELETE_ATTR=96, /* 0x60 */
00190     STORE_GLOBAL=97, /* 0x61 */
00191     DELETE_GLOBAL=98, /* 0x62 */
00192     DUP_TOPX=99, /* 0x63 */
00193     LOAD_CONST=100, /* 0x64 */
00194     LOAD_NAME=101, /* 0x65 */
00195     BUILD_TUPLE=102, /* 0x66 */
00196     BUILD_LIST=103, /* 0x67 */
00197     BUILD_SET=104, /* 0x68 */
00198     BUILD_MAP=105, /* 0x69 */
00199     LOAD_ATTR=106, /* 0x6a */
00200     COMPARE_OP=107, /* 0x6b */
00201     IMPORT_NAME=108, /* 0x6c */
00202     IMPORT_FROM=109, /* 0x6d */
00203     JUMP_FORWARD=110, /* 0x6e */
00204     JUMP_IF_FALSE_OR_POP=111, /* 0x6f */
00205     JUMP_IF_TRUE_OR_POP=112, /* 0x70 */
00206     JUMP_ABSOLUTE=113, /* 0x71 */
00207     POP_JUMP_IF_FALSE=114, /* 0x72 */
00208     POP_JUMP_IF_TRUE=115, /* 0x73 */
00209     LOAD_GLOBAL=116, /* 0x74 */
00210     UNUSED_75=117,
00211     UNUSED_76=118,
00212     CONTINUE_LOOP=119, /* 0x77 */
00213     SETUP_LOOP=120, /* 0x78 */
00214     SETUP_EXCEPT=121, /* 0x79 */
00215     SETUP_FINALLY=122, /* 0x7a */
00216     UNUSED_7B=123,
00217     LOAD_FAST=124, /* 0x7c */
00218     STORE_FAST=125, /* 0x7d */
00219     DELETE_FAST=126, /* 0x7e */
00220     UNUSED_7F=127,
00221     UNUSED_80=128,
00222     UNUSED_81=129,
00223     RAISE_VARARGS=130, /* 0x82 */
00224     CALL_FUNCTION=131, /* 0x83 */
00225     MAKE_FUNCTION=132, /* 0x84 */
00226     BUILD_SLICE=133, /* 0x85 */
00227     MAKE_CLOSURE=134, /* 0x86 */
00228     LOAD_CLOSURE=135, /* 0x87 */
00229     LOAD_DEREF=136, /* 0x88 */
00230     STORE_DEREF=137, /* 0x89 */
00231     UNUSED_8A=138,
00232     UNUSED_8B=139,
00233     CALL_FUNCTION_VAR=140, /* 0x8c */
00234     CALL_FUNCTION_KW=141, /* 0x8d */
00235     CALL_FUNCTION_VAR_KW=142, /* 0x8e */
00236     SETUP_WITH=143, /* 0x8f */
00237     UNUSED_90=144,
00238     EXTENDED_ARG=145, /* 0x91 */
00239     SET_ADD=146, /* 0x92 */
00240     MAP_ADD=147, /* 0x93 */
00241     UNUSED_94=148,
00242     UNUSED_95=149,
00243     UNUSED_96=150,
00244     UNUSED_97=151,
00245     UNUSED_98=152,
00246     UNUSED_99=153,
00247     UNUSED_9A=154,
00248     UNUSED_9B=155,
00249     UNUSED_9C=156,
00250     UNUSED_9D=157,
00251     UNUSED_9E=158,
00252     UNUSED_9F=159,
00253     UNUSED_A0=160,
00254     UNUSED_A1=161,
00255     UNUSED_A2=162,
00256     UNUSED_A3=163,
00257     UNUSED_A4=164,
00258     UNUSED_A5=165,
00259     UNUSED_A6=166,
00260     UNUSED_A7=167,
00261     UNUSED_A8=168,
00262     UNUSED_A9=169,
00263     UNUSED_AA=170,
00264     UNUSED_AB=171,
00265     UNUSED_AC=172,
00266     UNUSED_AD=173,
00267     UNUSED_AE=174,
00268     UNUSED_AF=175,
00269     UNUSED_B0=176,
00270     UNUSED_B1=177,
00271     UNUSED_B2=178,
00272     UNUSED_B3=179,
00273     UNUSED_B4=180,
00274     UNUSED_B5=181,
00275     UNUSED_B6=182,
00276     UNUSED_B7=183,
00277     UNUSED_B8=184,
00278     UNUSED_B9=185,
00279     UNUSED_BA=186,
00280     UNUSED_BB=187,
00281     UNUSED_BC=188,
00282     UNUSED_BD=189,
00283     UNUSED_BE=190,
00284     UNUSED_BF=191,
00285     UNUSED_C0=192,
00286     UNUSED_C1=193,
00287     UNUSED_C2=194,
00288     UNUSED_C3=195,
00289     UNUSED_C4=196,
00290     UNUSED_C5=197,
00291     UNUSED_C6=198,
00292     UNUSED_C7=199,
00293     UNUSED_C8=200,
00294     UNUSED_C9=201,
00295     UNUSED_CA=202,
00296     UNUSED_CB=203,
00297     UNUSED_CC=204,
00298     UNUSED_CD=205,
00299     UNUSED_CE=206,
00300     UNUSED_CF=207,
00301     UNUSED_D0=208,
00302     UNUSED_D1=209,
00303     UNUSED_D2=210,
00304     UNUSED_D3=211,
00305     UNUSED_D4=212,
00306     UNUSED_D5=213,
00307     UNUSED_D6=214,
00308     UNUSED_D7=215,
00309     UNUSED_D8=216,
00310     UNUSED_D9=217,
00311     UNUSED_DA=218,
00312     UNUSED_DB=219,
00313     UNUSED_DC=220,
00314     UNUSED_DD=221,
00315     UNUSED_DE=222,
00316     UNUSED_DF=223,
00317     UNUSED_E0=224,
00318     UNUSED_E1=225,
00319     UNUSED_E2=226,
00320     UNUSED_E3=227,
00321     UNUSED_E4=228,
00322     UNUSED_E5=229,
00323     UNUSED_E6=230,
00324     UNUSED_E7=231,
00325     UNUSED_E8=232,
00326     UNUSED_E9=233,
00327     UNUSED_EA=234,
00328     UNUSED_EB=235,
00329     UNUSED_EC=236,
00330     UNUSED_ED=237,
00331     UNUSED_EE=238,
00332     UNUSED_EF=239,
00333     UNUSED_F0=240,
00334     UNUSED_F1=241,
00335     UNUSED_F2=242,
00336     UNUSED_F3=243,
00337     UNUSED_F4=244,
00338     UNUSED_F5=245,
00339     UNUSED_F6=246,
00340     UNUSED_F7=247,
00341     UNUSED_F8=248,
00342     UNUSED_F9=249,
00343     UNUSED_FA=250,
00344     UNUSED_FB=251,
00345     UNUSED_FC=252,
00346     UNUSED_FD=253,
00347     UNUSED_FE=254,
00348     UNUSED_FF=255,
00349 #else /* HAVE_PYTHON27 */
00350     /*
00351      * Python source to create this list:
00352      * import dis
00353      * o = dis.opname
00354      * for i in range(256):
00355      *     if o[i][0] != '<':
00356      *         print "\t%s," % o[i]
00357      *     else:
00358      *         print "\tUNUSED_%02X," % i
00359      */
00360     STOP_CODE = 0,              /* 0x00 */
00361     POP_TOP,
00362     ROT_TWO,
00363     ROT_THREE,
00364     DUP_TOP,
00365     ROT_FOUR,
00366     UNUSED_06,
00367     UNUSED_07,
00368     UNUSED_08,
00369     NOP,
00370     UNARY_POSITIVE,             /* d010 */
00371     UNARY_NEGATIVE,
00372     UNARY_NOT,
00373     UNARY_CONVERT,
00374     UNUSED_0E,
00375     UNARY_INVERT,
00376     UNUSED_10,                  /* 0x10 */
00377     UNUSED_11,
00378     LIST_APPEND,
00379     BINARY_POWER,
00380     BINARY_MULTIPLY,            /* d020 */
00381     BINARY_DIVIDE,
00382     BINARY_MODULO,
00383     BINARY_ADD,
00384     BINARY_SUBTRACT,
00385     BINARY_SUBSCR,
00386     BINARY_FLOOR_DIVIDE,
00387     BINARY_TRUE_DIVIDE,
00388     INPLACE_FLOOR_DIVIDE,
00389     INPLACE_TRUE_DIVIDE,
00390     SLICE_0,                    /* d030 */
00391     SLICE_1,
00392     SLICE_2,                    /* 0x20 */
00393     SLICE_3,
00394     UNUSED_22,
00395     UNUSED_23,
00396     UNUSED_24,
00397     UNUSED_25,
00398     UNUSED_26,
00399     UNUSED_27,
00400     STORE_SLICE_0,              /* d040 */
00401     STORE_SLICE_1,
00402     STORE_SLICE_2,
00403     STORE_SLICE_3,
00404     UNUSED_2C,
00405     UNUSED_2D,
00406     UNUSED_2E,
00407     UNUSED_2F,
00408     UNUSED_30,                  /* 0x30 */
00409     UNUSED_31,
00410     DELETE_SLICE_0,             /* d050 */
00411     DELETE_SLICE_1,
00412     DELETE_SLICE_2,
00413     DELETE_SLICE_3,
00414     STORE_MAP,
00415     INPLACE_ADD,
00416     INPLACE_SUBTRACT,
00417     INPLACE_MULTIPLY,
00418     INPLACE_DIVIDE,
00419     INPLACE_MODULO,
00420     STORE_SUBSCR,               /* d060 */
00421     DELETE_SUBSCR,
00422     BINARY_LSHIFT,
00423     BINARY_RSHIFT,
00424     BINARY_AND,                 /* 0x40 */
00425     BINARY_XOR,
00426     BINARY_OR,
00427     INPLACE_POWER,
00428     GET_ITER,
00429     UNUSED_45,
00430     PRINT_EXPR,                 /* d070 */
00431     PRINT_ITEM,
00432     PRINT_NEWLINE,
00433     PRINT_ITEM_TO,
00434     PRINT_NEWLINE_TO,
00435     INPLACE_LSHIFT,
00436     INPLACE_RSHIFT,
00437     INPLACE_AND,
00438     INPLACE_XOR,
00439     INPLACE_OR,
00440     BREAK_LOOP,                 /* 0x50 *//* d080 */
00441     WITH_CLEANUP,
00442     LOAD_LOCALS,
00443     RETURN_VALUE,
00444     IMPORT_STAR,
00445     EXEC_STMT,
00446     YIELD_VALUE,
00447     POP_BLOCK,
00448     END_FINALLY,
00449     BUILD_CLASS,
00450 
00451     /* Opcodes from here have an argument */
00452     HAVE_ARGUMENT = 90,         /* d090 */
00453     STORE_NAME = 90,
00454     DELETE_NAME,
00455     UNPACK_SEQUENCE,
00456     FOR_ITER,
00457     UNUSED_5E,
00458     STORE_ATTR,
00459     DELETE_ATTR,                /* 0x60 */
00460     STORE_GLOBAL,
00461     DELETE_GLOBAL,
00462     DUP_TOPX,
00463     LOAD_CONST,                 /* d100 */
00464     LOAD_NAME,
00465     BUILD_TUPLE,
00466     BUILD_LIST,
00467     BUILD_MAP,
00468     LOAD_ATTR,
00469     COMPARE_OP,
00470     IMPORT_NAME,
00471     IMPORT_FROM,
00472     UNUSED_6D,
00473     JUMP_FORWARD,               /* d110 */
00474     JUMP_IF_FALSE,
00475     JUMP_IF_TRUE,               /* 0x70 */
00476     JUMP_ABSOLUTE,
00477     UNUSED_72,
00478     UNUSED_73,
00479     LOAD_GLOBAL,
00480     UNUSED_75,
00481     UNUSED_76,
00482     CONTINUE_LOOP,
00483     SETUP_LOOP,                 /* d120 */
00484     SETUP_EXCEPT,
00485     SETUP_FINALLY,
00486     UNUSED_7B,
00487     LOAD_FAST,
00488     STORE_FAST,
00489     DELETE_FAST,
00490     UNUSED_79,
00491     UNUSED_80,                  /* 0x80 */
00492     UNUSED_81,
00493     RAISE_VARARGS,              /* d130 */
00494     CALL_FUNCTION,
00495     MAKE_FUNCTION,
00496     BUILD_SLICE,
00497     MAKE_CLOSURE,
00498     LOAD_CLOSURE,
00499     LOAD_DEREF,
00500     STORE_DEREF,
00501     UNUSED_8A,
00502     UNUSED_8B,
00503     CALL_FUNCTION_VAR,          /* d140 */
00504     CALL_FUNCTION_KW,
00505     CALL_FUNCTION_VAR_KW,
00506     EXTENDED_ARG,
00507 
00508     UNUSED_90, UNUSED_91, UNUSED_92, UNUSED_93,
00509     UNUSED_94, UNUSED_95, UNUSED_96, UNUSED_97,
00510     UNUSED_98, UNUSED_99, UNUSED_9A, UNUSED_9B,
00511     UNUSED_9C, UNUSED_9D, UNUSED_9E, UNUSED_9F,
00512     UNUSED_A0, UNUSED_A1, UNUSED_A2, UNUSED_A3,
00513     UNUSED_A4, UNUSED_A5, UNUSED_A6, UNUSED_A7,
00514     UNUSED_A8, UNUSED_A9, UNUSED_AA, UNUSED_AB,
00515     UNUSED_AC, UNUSED_AD, UNUSED_AE, UNUSED_AF,
00516     UNUSED_B0, UNUSED_B1, UNUSED_B2, UNUSED_B3,
00517     UNUSED_B4, UNUSED_B5, UNUSED_B6, UNUSED_B7,
00518     UNUSED_B8, UNUSED_B9, UNUSED_BA, UNUSED_BB,
00519     UNUSED_BC, UNUSED_BD, UNUSED_BE, UNUSED_BF,
00520     UNUSED_C0, UNUSED_C1, UNUSED_C2, UNUSED_C3,
00521     UNUSED_C4, UNUSED_C5, UNUSED_C6, UNUSED_C7,
00522     UNUSED_C8, UNUSED_C9, UNUSED_CA, UNUSED_CB,
00523     UNUSED_CC, UNUSED_CD, UNUSED_CE, UNUSED_CF,
00524     UNUSED_D0, UNUSED_D1, UNUSED_D2, UNUSED_D3,
00525     UNUSED_D4, UNUSED_D5, UNUSED_D6, UNUSED_D7,
00526     UNUSED_D8, UNUSED_D9, UNUSED_DA, UNUSED_DB,
00527     UNUSED_DC, UNUSED_DD, UNUSED_DE, UNUSED_DF,
00528     UNUSED_E0, UNUSED_E1, UNUSED_E2, UNUSED_E3,
00529     UNUSED_E4, UNUSED_E5, UNUSED_E6, UNUSED_E7,
00530     UNUSED_E8, UNUSED_E9, UNUSED_EA, UNUSED_EB,
00531     UNUSED_EC, UNUSED_ED, UNUSED_EE, UNUSED_EF,
00532     UNUSED_F0, UNUSED_F1, UNUSED_F2, UNUSED_F3,
00533     UNUSED_F4, UNUSED_F5, UNUSED_F6, UNUSED_F7,
00534     UNUSED_F8, UNUSED_F9, UNUSED_FA, UNUSED_FB,
00535     UNUSED_FC, UNUSED_FD, UNUSED_FE, UNUSED_FF
00536 #endif /* HAVE_PYTHON27 */
00537 } PmBcode_t, *pPmBcode_t;
00538 
00539 
00540 /**
00541  * Interprets the available threads. Does not return.
00542  *
00543  * @param returnOnNoThreads Loop forever if 0, exit with status if no more
00544  *                          threads left.
00545  * @return Return status if called with returnOnNoThreads != 0,
00546  *         will not return otherwise.
00547  */
00548 PmReturn_t interpret(const uint8_t returnOnNoThreads);
00549 
00550 /**
00551  * Selects a thread to run and changes the VM internal variables to
00552  * let the switch-loop execute the chosen one in the next iteration.
00553  * For the moment the algorithm is primitive and will change the
00554  * thread each time it is called in a round-robin fashion.
00555  */
00556 PmReturn_t interp_reschedule(void);
00557 
00558 /**
00559  * Creates a thread object and adds it to the queue of threads to be
00560  * executed while interpret() is running.
00561  *
00562  * The given obj may be a function, module, or class.
00563  * Creates a frame for the given function.
00564  *
00565  * @param pfunc Ptr to function to be executed as a thread.
00566  * @return Return status
00567  */
00568 PmReturn_t interp_addThread(pPmFunc_t pfunc);
00569 
00570 /**
00571  * Sets the  reschedule flag.
00572  *
00573  * @param boolean Reschedule on next occasion if boolean is true; clear
00574  *                the flag otherwise.
00575  */
00576 void interp_setRescheduleFlag(uint8_t boolean);
00577 
00578 #endif /* __INTERP_H__ */