/* * Wedge.c * by Bart Whitebook * * Copyright (c) 1988 Commodore-Amiga, Inc. * * Executables based on this information may be used in software * for Commodore Amiga computers. All other rights reserved. * * This information is provided "as is"; no warranties are made. * All use is at your own risk, and no liability or responsibility is assumed. */ /* This code was created under Greenhills. * It compiles under Manx with the cflags: * * +L +C +D +p -B -S -L100 */ /****************************************************************************** * * Source Control * -------------- * $Header: wedge.c,v 35.8 88/03/23 09:51:24 bart Exp $ * * $Locker: $ * * $Log: wedge.c,v $ * Revision 35.8 88/03/23 09:51:24 bart * remove() mods * * Revision 35.7 88/03/22 18:55:42 bart * if(wp) in dispose * * Revision 35.6 88/03/22 15:17:24 bart * keep opencount * * Revision 35.0 88/03/01 11:20:28 bart * added to rcs for updating * * ******************************************************************************/ #include #include #include #include #include #ifdef DEBUG #define KPRINTF #endif #ifdef KPRINTF #define printf kprintf #endif #define JSR_ABS 0x4EB9 #define JSR_dPC 0x4EBA #define JMP_ABS 0x4EF9 #define JMP_dPC 0x4EFA #define RTS 0x4E75 struct Wedge { UWORD wedge_Vectors[20]; struct Library wedge_Library; WORD wedge_Offset; } ; /* support code for usecount */ #define MOVEM_REG_SP 0x48E7 #define REG_TO_MEM 0x0080 #define LEA_dPC 0x41FA #define ADDQ_1 0x5250 #define SUBQ_1 0x5350 #define NO_OP 0x4E71 #define MOVEM_SP_REG 0x4CDF #define MEM_TO_REG 0x0100 new_wedge() { struct Wedge *wp = NULL; /* allocate a wedge */ if(wp=(struct Wedge *)AllocMem(sizeof(struct Wedge),MEMF_PUBLIC|MEMF_CLEAR)) { /* initialize the wedge library to default values */ wp->wedge_Library.lib_Node.ln_Type = NT_LIBRARY; wp->wedge_Library.lib_NegSize = 12; wp->wedge_Library.lib_PosSize = sizeof(struct Library)+sizeof(WORD); wp->wedge_Library.lib_Version = 35; wp->wedge_Library.lib_Revision = 1; /* initialize the wedge vectors to default values */ wp->wedge_Vectors[0] = MOVEM_REG_SP; /* increment opencount */ wp->wedge_Vectors[1] = REG_TO_MEM; wp->wedge_Vectors[2] = LEA_dPC; wp->wedge_Vectors[3] = 0x0042; wp->wedge_Vectors[4] = ADDQ_1; wp->wedge_Vectors[5] = MOVEM_SP_REG; wp->wedge_Vectors[6] = MEM_TO_REG; wp->wedge_Vectors[7] = JSR_dPC; /* do wedge function */ wp->wedge_Vectors[8] = 0x0004; /* default */ wp->wedge_Vectors[9] = RTS; /* return */ wp->wedge_Vectors[10] = MOVEM_REG_SP; /* decrement opencount */ wp->wedge_Vectors[11] = REG_TO_MEM; wp->wedge_Vectors[12] = LEA_dPC; wp->wedge_Vectors[13] = 0x002E; wp->wedge_Vectors[14] = SUBQ_1; wp->wedge_Vectors[15] = MOVEM_SP_REG; wp->wedge_Vectors[16] = MEM_TO_REG; wp->wedge_Vectors[17] = JMP_dPC; /* do old function */ wp->wedge_Vectors[18] = 0x0002; /* default */ wp->wedge_Vectors[19] = RTS; /* return */ } return((ULONG)wp); } dispose_wedge(wp) struct Wedge *wp; { /* to be strict, we must assume that some task's pc is */ /* about to execute this wedge: so we must leave the wedge */ /* in memory until the opencount of this wedge is 0 before */ /* we are free to delink the wedge "function"... not that the */ /* wedge structure itself must remain in memory when we are gone */ if(wp) { Forbid(); while(wp->wedge_Library.lib_OpenCnt != 0) WaitTOF(); Disable(); wp->wedge_Vectors[7] = JSR_dPC; /* install default function */ wp->wedge_Vectors[8] = 0x0004; /* in place of wedge function */ wp->wedge_Vectors[9] = RTS; /* and return */ Enable(); Permit(); } } test_wedge(wp) struct Wedge *wp; { ULONG is_wedge = NULL; UBYTE *pred; /* make certain that wp is not odd -- it will be if wp == default vector */ if(((ULONG)wp)^1) { if(wp->wedge_Library.lib_Node.ln_Type == NT_LIBRARY) { if(pred = wp->wedge_Library.lib_Node.ln_Pred) { if(((ULONG)pred)^1) { if(wp==(struct Wedge *)*(ULONG *)(pred+wp->wedge_Offset+2)) { is_wedge = (ULONG)wp; } } } } } return(is_wedge); } link_wedge(lib,offset,wedge) UBYTE *lib; WORD offset; struct Wedge *wedge; { ULONG is_wedge = NULL; struct Wedge *owp; UBYTE *pred; if(owp = (struct Wedge *)test_wedge(*(ULONG *)(lib+offset+2))) { is_wedge = (ULONG)owp; owp->wedge_Library.lib_Node.ln_Pred = wedge; owp->wedge_Offset = -6; } return(is_wedge); } delink_wedge(lib,offset,wp) UBYTE *lib; WORD offset; struct Wedge *wp; { struct Wedge *owp = NULL; struct Wedge *nwp; if(wp) { /* prevent unpleasant suprises */ Disable(); /* is this still a valid wedge? */ if(owp = (struct Wedge *)test_wedge(wp)) { struct Library *pred = owp->wedge_Library.lib_Node.ln_Pred; /* yes, valid. does this wedge point to another wedge? */ if( nwp = (struct Wedge *) test_wedge(*(ULONG *)(&owp->wedge_Vectors[18])) ) { nwp->wedge_Library.lib_Node.ln_Pred = pred; } /* does the previous library point to this wedge's library */ if(pred->lib_Node.ln_Succ == &owp->wedge_Library) { /* yes, make previous library point to next wedge's library */ pred->lib_Node.ln_Succ == &nwp->wedge_Library; } /* make previous vector point to next vector */ SetFunction( wp->wedge_Library.lib_Node.ln_Pred, wp->wedge_Offset, *(ULONG *)(&wp->wedge_Vectors[18])); /* now the wedge is delinked... */ } else { /* wedge not validated... */ /* assume that has been setfunction'ed away, */ /* and may be setfunction'ed back in the near future: */ /* install default function, if wedge not in use */ if(wp->wedge_Library.lib_OpenCnt == 0) { wp->wedge_Vectors[7] = JSR_dPC; wp->wedge_Vectors[8] = 0x0004; wp->wedge_Vectors[9] = RTS; } } /* suprises ok now, i guess... */ Enable(); } return((ULONG)owp); } install_wedge(lib,offset,entry) struct Library *lib; WORD offset; ULONG entry; { struct Wedge *wp = NULL; if( (entry) && (wp = (struct Wedge *)new_wedge()) ) { /* prevent unpleasant suprises */ Disable(); /* point this wedge at our new entry */ wp->wedge_Vectors[7] = JSR_ABS; *(ULONG *)(&wp->wedge_Vectors[8]) = entry; /* point this wedge at the previous entry */ wp->wedge_Library.lib_Node.ln_Pred = lib; wp->wedge_Offset = offset; /* link this wedge to existing wedge? */ wp->wedge_Library.lib_Node.ln_Succ = (struct Node *) link_wedge(lib,offset,wp); /* install this wedge in place of the old entry */ wp->wedge_Vectors[17] = JMP_ABS; *(ULONG *)(&wp->wedge_Vectors[18]) = SetFunction(lib,offset,wp); /* suprises ok now, i guess... */ Enable(); } return((ULONG)wp); } remove_wedge(wedge) struct Wedge *wedge; { delink_wedge(wedge); dispose_wedge(wedge); }