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111 lines
3.5 KiB
C
111 lines
3.5 KiB
C
/*
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** Copyright (c) 1996
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** Michael Smith. All rights reserved.
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**
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** Redistribution and use in source and binary forms, with or without
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** modification, are permitted provided that the following conditions
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** are met:
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** 1. Redistributions of source code must retain the above copyright
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** notice, this list of conditions and the following disclaimer.
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** 2. Redistributions in binary form must reproduce the above copyright
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** notice, this list of conditions and the following disclaimer in the
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** documentation and/or other materials provided with the distribution.
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**
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** THIS SOFTWARE IS PROVIDED BY Michael Smith ``AS IS'' AND
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** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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** ARE DISCLAIMED. IN NO EVENT SHALL Michael Smith BE LIABLE
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** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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** OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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** HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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** OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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** SUCH DAMAGE.
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**
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** $FreeBSD$
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*/
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/*
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** Interrupt dispatcher assistants.
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*/
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/*
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** Declare a static, initialised array of these, with one
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** entry per function/subfunction.
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**
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** The last element should be a dummy with a 'func' of -1
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*/
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struct intfunc_table
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{
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int func; /* interrupt function number */
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int subfunc; /* subfunction number */
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int (* handler)(regcontext_t *REGS);/* handling function */
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const char *desc; /* textual description */
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};
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#define IFT_NOSUBFUNC -1
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/*
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** Declare a static array of 256 integers to use as a fast lookup
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** into the table of handlers.
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**
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** Call this function to initialise the lookup. Note that the table
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** must be arranged with all handlers for a given function together, and
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** that the handler listed with IFT_NOSUBFUNC should be last.
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*/
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static inline void
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intfunc_init(struct intfunc_table table[], int index[])
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{
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int hn;
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for (hn = 0; hn < 256; hn++) /* initialise all no-handler state */
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index[hn] = -1; /* default to no handler */
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for (hn = 0; table[hn].func >= 0; hn++) /* walk list of handlers and add references */
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if (index[table[hn].func] == -1 ) /* reference first handler */
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index[table[hn].func] = hn;
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}
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/*
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** Call this to get an index matching the function/subfunction
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** described by (sc), or -1 if none exist
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*/
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static inline int
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intfunc_find(struct intfunc_table table[], int index[], int func, int subfunc)
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{
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int ent = index[func]; /* look for handler */
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while ((ent >= 0) && /* scan entries for function */
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(table[ent].func == func)) {
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if ((table[ent].subfunc == IFT_NOSUBFUNC) || /* handles all */
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(table[ent].subfunc == subfunc)) { /* handles this one */
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return(ent);
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}
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ent++;
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}
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return(-1);
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}
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/*
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** A slower lookup for a set of function handlers, but one that requires
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** no initialisation calls.
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** Again, handlers with IFT_NOSUBFUNC should be listed after any with
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** specific subfunction values.
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*/
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static inline int
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intfunc_search(struct intfunc_table table[], int func, int subfunc)
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{
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int ent;
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for (ent = 0; table[ent].func >= 0; ent++)
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if ((table[ent].func == func) && /* matches required function */
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((table[ent].subfunc == IFT_NOSUBFUNC) || table[ent].subfunc == subfunc))
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return(ent);
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return(-1);
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}
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