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Annotation of gforth/decstation.h, revision 1.1

1.1     ! anton       1: /*
        !             2:   $Id: decstation.h,v 1.8 1993/05/25 10:24:18 anton Exp $
        !             3:   Copyright 1992 by the ANSI figForth Development Group
        !             4: 
        !             5:   This is the machine-specific part for a Decstation running Ultrix
        !             6: */
        !             7: 
        !             8: 
        !             9: /* Cell and UCell must be the same size as a pointer */
        !            10: typedef long Cell;
        !            11: typedef unsigned long UCell;
        !            12: 
        !            13: /* DCell and UDCell must be twice as large as Cell */
        !            14: typedef long long DCell;
        !            15: typedef unsigned long long UDCell;
        !            16: 
        !            17: /* define this if IEEE singles and doubles are available as C data types */
        !            18: #define IEEE_FP
        !            19: 
        !            20: /* the IEEE types are used only for loading and storing */
        !            21: /* the IEEE double precision type */
        !            22: typedef double DFloat;
        !            23: /* the IEEE single precision type */
        !            24: typedef float SFloat;
        !            25: 
        !            26: /* define this if the least-significant byte is at the largets address */
        !            27: /* #define BIG_ENDIAN */
        !            28: 
        !            29: /* some definitions for composing opcodes */
        !            30: #define JUMP_MASK      0x03ffffff
        !            31: #define J_PATTERN      0x08000000
        !            32: #define JAL_PATTERN    0x0c000000
        !            33: /* this provides the first 4 bits of a jump address, i.e. it must be <16 */
        !            34: #define SEGMENT_NUM    1
        !            35: 
        !            36: #ifdef DIRECT_THREADED
        !            37:        /* PFA gives the parameter field address corresponding to a cfa */
        !            38: #      define PFA(cfa) (((Cell *)cfa)+2)
        !            39:        /* PFA1 is a special version for use just after a NEXT1 */
        !            40: #      define PFA1(cfa)        PFA(cfa)
        !            41:        /* CODE_ADDRESS is the address of the code jumped to through the code field */
        !            42: #      define CODE_ADDRESS(cfa)        ((Label)(((*(unsigned *)(cfa))^J_PATTERN^(SEGMENT_NUM<<26))<<2))
        !            43:        /* MAKE_CF creates an appropriate code field at the cfa; ca is the code address */
        !            44: #      define MAKE_CF(cfa,ca)  ({long * _cfa = (long *)(cfa); \
        !            45:                                          _cfa[0] = J_PATTERN|((((long)(ca))&JUMP_MASK)>>2); /* J ca */ \
        !            46:                                          _cfa[1] = 0; /* nop */})
        !            47: #      ifdef undefined
        !            48:                /* the following version uses JAL to make PFA1 faster */
        !            49: #              define PFA1(label)      ({register Cell *pfa asm("$31"); \
        !            50:                                                pfa; })
        !            51:                /* CODE_ADDRESS is the address of the code jumped to through the code field */
        !            52: #              define CODE_ADDRESS(cfa)        ((Label)(((*(unsigned *)(cfa))^JAL_PATTERN^(SEGMENT_NUM<<26))<<2))
        !            53: #              define MAKE_CF(cfa,ca)  ({long *_cfa = (long *)(cfa); \
        !            54:                                          long _ca = (long)(ca);
        !            55:                                                  _cfa[0] = JAL_PATTERN|(((((long)_ca)>>2)+4)&JUMP_MASK), /* JAL ca+4 */ \
        !            56:                                                  _cfa[1] = *(long *)_ca; /* delay slot */})
        !            57: #      endif /* undefined */
        !            58: 
        !            59:        /* this is the point where the does code starts if label points to the
        !            60:         * jump dodoes */
        !            61: #      define DOES_CODE(cfa)   ((Xt *)(((char *)CODE_ADDRESS(cfa))+8))
        !            62: 
        !            63:        /* this is a special version of DOES_CODE for use in dodoes */
        !            64: #      define DOES_CODE1(cfa)  DOES_CODE(cfa)
        !            65: 
        !            66: #      define DOES_HANDLER_SIZE        8
        !            67: #      define MAKE_DOES_CF(cfa, does_code)     ({char *does_handlerp=((char *)does_code)-DOES_HANDLER_SIZE;    \
        !            68:                                                  MAKE_CF(cfa,does_handlerp);   \
        !            69:                                                  MAKE_DOES_HANDLER(does_handlerp);})
        !            70:        /* this stores a jump dodoes at addr */
        !            71: #      define MAKE_DOES_HANDLER(addr)  ({long * _addr = (long *)addr; \
        !            72:                                          _addr[0] = J_PATTERN|((((long)DODOES)>>2)&JUMP_MASK); /* J dodoes */ \
        !            73:                                          _addr[1] = 0; /* nop */})
        !            74: #endif
        !            75: #ifdef undefined
        !            76: /* and here are some more efficient versions that can be tried later */
        !            77: 
        !            78: /* the first version saves one cycle by doing something useful in the
        !            79:    delay slot. !! check that the instruction in the delay slot is legal
        !            80: */
        !            81: 
        !            82: #define MAKE_DOESJUMP(addr)    ({long * _addr = (long *)addr; \
        !            83:                                  _addr[0] = J_PATTERN|(((((long)symbols[3])>>2)+4)&JUMP_MASK), /* J dodoes+4 */ \
        !            84:                                  _addr[1] = *(long *)symbols[3]; /* delay */})
        !            85: 
        !            86: /* the following version uses JAL to make DOES_CODE1 faster */
        !            87: /* !! does the declaration clear the register ? */
        !            88: /* it's ok to use the same reg as in PFA1:
        !            89:    dodoes is the only potential problem and I have taken care of it */
        !            90: #define DOES_CODE1(cfa)        ({register Code *_does_code asm("$31"); \
        !            91:                                    _does_code; })
        !            92: #define MAKE_DOESJUMP(addr)    ({long * _addr = (long *)addr; \
        !            93:                                  _addr[0] = JAL_PATTERN|(((((long)symbols[3])>>2)+4)&JUMP_MASK), /* JAL dodoes+4 */ \
        !            94:                                  _addr[1] = *(long *)symbols[3]; /* delay */})
        !            95: 
        !            96: #endif