Annotation of gforth/power.h, revision 1.1
1.1 ! anton 1: /*
! 2: Copyright 1992 by the ANSI figForth Development Group
! 3:
! 4: This is the machine-specific part for the Power (incl. PPC) architecture
! 5: */
! 6:
! 7: #if !defined(USE_TOS) && !defined(USE_NO_TOS)
! 8: #define USE_TOS
! 9: #endif
! 10:
! 11: #ifndef INDIRECT_THREADED
! 12: #ifndef DIRECT_THREADED
! 13: /* #define DIRECT_THREADED */
! 14: #endif
! 15: #endif
! 16:
! 17: #include "32bit.h"
! 18:
! 19: /* cache flush stuff */
! 20: #ifdef DIRECT_THREADED
! 21: #warning Direct threading for Power has not been tested
! 22:
! 23: #warning If you get assembly errors, here is the reason why
! 24: #define CACHE_FLUSH(addr,size) asm("icbi (%0); isync"::"b"(addr))
! 25: /* this assumes size=4 */
! 26: /* the mnemonics are for the PPC and the syntax is a wild guess; for
! 27: Power the mnemonic for the isync instruction is "ics" and I have
! 28: not found an equivalent for the icbi instruction in my reference.
! 29: */
! 30:
! 31: /* PFA gives the parameter field address corresponding to a cfa */
! 32: #define PFA(cfa) (((Cell *)cfa)+2)
! 33: /* PFA1 is a special version for use just after a NEXT1 */
! 34: /* the improvement here is that we may destroy cfa before using PFA1 */
! 35: #define PFA1(cfa) PFA(cfa)
! 36:
! 37: /* I'll assume the code resides in the lower (or upper) 32M of the
! 38: address space and use absolute addressing in the jumps to the
! 39: handlers. This makes it possible to use the full address space for
! 40: direct threaded Forth (even on 64-bit PowerPCs). However, the
! 41: linker has to ensure that this really happens */
! 42:
! 43: #define JUMP_TARGET_BITS 0
! 44: /* assuming the code is in the lower 32M; if it is in the upper 32M,
! 45: define JUMP_TARGET_BITS as ~0x3ffffff */
! 46: #define JUMP_MASK 0x3fffffc
! 47:
! 48: /* CODE_ADDRESS is the address of the code jumped to through the code field */
! 49: #define CODE_ADDRESS(cfa) ((Label)(((*(unsigned *)(cfa))&JUMP_MASK)|JUMP_TARGET_BITS))
! 50:
! 51: /* MAKE_CF creates an appropriate code field at the cfa; ca is the
! 52: code address. For those familiar with assembly, this is a `ba'
! 53: instruction in both Power and PowerPC assembly languages */
! 54: #define MAKE_CF(cfa,ca) (*(long *)(cfa) = 0x48000002|(ca))
! 55:
! 56: /* this is the point where the does code for the word with the xt cfa
! 57: starts. Since a branch is only a cell on Power, we can use the
! 58: second cell of the cfa for storing the does address */
! 59: #define DOES_CODE(cfa) ((Xt *)(((long *)(cfa))[1]))
! 60: /* this is a special version of DOES_CODE for use in dodoes */
! 61: #define DOES_CODE1(label) DOES_CODE(label)
! 62:
! 63: /* the does handler resides between DOES> and the following Forth
! 64: code. Since the code-field jumps directly to dodoes, the
! 65: does-handler is not needed for the Power architecture */
! 66: #define DOES_HANDLER_SIZE 8
! 67: #define MAKE_DOES_HANDLER(addr) 0
! 68:
! 69: /* This makes a code field for a does-defined word. doesp is the
! 70: address of the does-code. On the PPC, the code field consists of a
! 71: jump to dodoes and the address of the does code */
! 72: #define MAKE_DOES_CF(cfa,doesp) ({Xt *_cfa = (Xt *)(cfa); \
! 73: MAKE_CF(_cfa, symbols[DODOES]); \
! 74: _cfa[1] = (doesp); })
! 75: #endif
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