mirror of
https://github.com/Oibaf66/uae-wii.git
synced 2024-06-03 00:58:47 +02:00
85 lines
3.2 KiB
C
85 lines
3.2 KiB
C
/*
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* UAE - The Un*x Amiga Emulator
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*
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* MC68000 emulation - machine dependent bits
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*
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* Copyright 1996 Bernd Schmidt, Samuel Devulder
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* Copyright 2004-2007 Richard Drummond
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*/
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/*
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* Machine dependent structure for holding the 68k CCR flags
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*/
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struct flag_struct {
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unsigned short int cznv;
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unsigned short int x;
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};
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extern struct flag_struct regflags;
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/*
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* The bits in the cznv field are assigned in correspondence to the
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* CZNV flags in the 68k CCR register
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*/
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#define FLAGBIT_N 3
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#define FLAGBIT_Z 2
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#define FLAGBIT_V 1
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#define FLAGBIT_C 0
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#define FLAGBIT_X FLAGBIT_C
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#define FLAGVAL_N (1 << FLAGBIT_N)
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#define FLAGVAL_Z (1 << FLAGBIT_Z)
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#define FLAGVAL_C (1 << FLAGBIT_C)
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#define FLAGVAL_V (1 << FLAGBIT_V)
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#define FLAGVAL_X (1 << FLAGBIT_X)
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#define SET_ZFLG(flags, y) ((flags)->cznv = ((flags)->cznv & ~FLAGVAL_Z) | ((y) << FLAGBIT_Z))
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#define SET_CFLG(flags, y) ((flags)->cznv = ((flags)->cznv & ~FLAGVAL_C) | ((y) << FLAGBIT_C))
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#define SET_VFLG(flags, y) ((flags)->cznv = ((flags)->cznv & ~FLAGVAL_V) | ((y) << FLAGBIT_V))
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#define SET_NFLG(flags, y) ((flags)->cznv = ((flags)->cznv & ~FLAGVAL_N) | ((y) << FLAGBIT_N))
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#define SET_XFLG(flags, y) ((flags)->x = (y) << FLAGBIT_X)
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#define GET_ZFLG(flags) (((flags)->cznv >> FLAGBIT_Z) & 1)
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#define GET_CFLG(flags) (((flags)->cznv >> FLAGBIT_C) & 1)
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#define GET_VFLG(flags) (((flags)->cznv >> FLAGBIT_V) & 1)
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#define GET_NFLG(flags) (((flags)->cznv >> FLAGBIT_N) & 1)
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#define GET_XFLG(flags) (((flags)->x >> FLAGBIT_X) & 1)
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#define CLEAR_CZNV(flags) ((flags)->cznv = 0)
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#define GET_CZNV(flags) ((flags)->cznv)
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#define IOR_CZNV(flags, X) ((flags)->cznv |= (X))
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#define SET_CZNV(flags, X) ((flags)->cznv = (X))
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#define COPY_CARRY(flags) ((flags)->x = (flags)->cznv)
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/*
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* Test CCR condition
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*/
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STATIC_INLINE int cctrue (const struct flag_struct *flags, int cc)
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{
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uae_u32 cznv = flags->cznv;
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switch (cc) {
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case 0: return 1; /* T */
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case 1: return 0; /* F */
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case 2: return (cznv & (FLAGVAL_C | FLAGVAL_Z)) == 0; /* !CFLG && !ZFLG HI */
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case 3: return (cznv & (FLAGVAL_C | FLAGVAL_Z)) != 0; /* CFLG || ZFLG LS */
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case 4: return (cznv & FLAGVAL_C) == 0; /* !CFLG CC */
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case 5: return (cznv & FLAGVAL_C) != 0; /* CFLG CS */
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case 6: return (cznv & FLAGVAL_Z) == 0; /* !ZFLG NE */
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case 7: return (cznv & FLAGVAL_Z) != 0; /* ZFLG EQ */
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case 8: return (cznv & FLAGVAL_V) == 0; /* !VFLG VC */
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case 9: return (cznv & FLAGVAL_V) != 0; /* VFLG VS */
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case 10: return (cznv & FLAGVAL_N) == 0; /* !NFLG PL */
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case 11: return (cznv & FLAGVAL_N) != 0; /* NFLG MI */
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case 12: return (((cznv << (FLAGBIT_N - FLAGBIT_V)) ^ cznv) & FLAGVAL_N) == 0; /* NFLG == VFLG GE */
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case 13: return (((cznv << (FLAGBIT_N - FLAGBIT_V)) ^ cznv) & FLAGVAL_N) != 0; /* NFLG != VFLG LT */
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case 14: cznv &= (FLAGVAL_N | FLAGVAL_Z | FLAGVAL_V); /* ZFLG && (NFLG == VFLG) GT */
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return (((cznv << (FLAGBIT_N - FLAGBIT_V)) ^ cznv) & (FLAGVAL_N | FLAGVAL_Z)) == 0;
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case 15: cznv &= (FLAGVAL_N | FLAGVAL_Z | FLAGVAL_V); /* ZFLG && (NFLG != VFLG) LE */
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return (((cznv << (FLAGBIT_N - FLAGBIT_V)) ^ cznv) & (FLAGVAL_N | FLAGVAL_Z)) != 0;
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}
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abort ();
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return 0;
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}
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