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Interlisp.maiko/src/hardrtn.c
Nick Briggs c097563730
The error() function may return under exceptional circumstances (#97) 
There are a few places where error() was called that in practice would never
be returned from, however since it was coded with the possibility of returning
all call sites must be consistent with that.

	modified:   ../src/car-cdr.c
	modified:   ../src/gchtfind.c
	modified:   ../src/hardrtn.c
2021-01-02 13:36:14 -08:00

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/* $Id: hardrtn.c,v 1.4 2001/12/24 01:09:02 sybalsky Exp $ (C) Copyright Venue, All Rights Reserved
*/
/************************************************************************/
/* */
/* (C) Copyright 1989-95 Venue. All Rights Reserved. */
/* Manufactured in the United States of America. */
/* */
/************************************************************************/
#include "version.h"
/********************************************************************/
/*
File Name : hardrtn.c
Edited by Takeshi Shimizu
Date: 10-MAY-88
RET VAL: If success: 0
else (NO SPACE in STACK) 1 -> should cause HARDRESET
*/
/********************************************************************/
#include <stdio.h>
#include "lispemul.h"
#include "lispmap.h"
#include "lsptypes.h"
#include "adr68k.h"
#include "address.h"
#include "lspglob.h"
#include "emlglob.h"
#include "cell.h"
#include "stack.h"
#include "return.h"
#include "hardrtndefs.h"
#include "commondefs.h"
#include "llstkdefs.h"
#define MAKE_FXCOPY(fx68k) \
{ \
BEFORE_CONTEXTSW; \
if ((fx68k = (FX *)make_FXcopy(fx68k)) == 0) { return (1); /* Whole space exhausted */ } \
AFTER_CONTEXTSW; \
CHECK_FX(fx68k); \
}
static FX *make_FXcopy(register FX *fx68k) {
register int size;
int nametbl_on_stk = NIL;
register DLword *new68k;
register Bframe *retbf68k;
#ifdef FLIPCURSOR
flip_cursorbar(5);
#endif
CHECK_FX(fx68k);
size = FX_size(fx68k) + DLWORDSPER_CELL;
#ifdef BIGVM
if (fx68k->validnametable && ((fx68k->nametable >> 16) == STK_HI))
#else
if (fx68k->validnametable && (fx68k->hi2nametable == STK_HI))
#endif /* BIGVM */
{
/* frame contains a name table, so we care that the alignment
of the new block be same as old */
#ifdef STACKCHECK
{
DLword n;
#ifdef BIGVM
n = fx68k->nametable & 0xFFFF;
#else
n = fx68k->lonametable;
#endif /* BIGVM */
if ((n <= StkOffset_from_68K(fx68k)) && (n >= fx68k->nextblock))
error("hardreturn:nametable check");
}
#endif
nametbl_on_stk = T;
/* Find a free stack block */
new68k = freestackblock(size, (StackWord *)CURRENTFX,
(StkOffset_from_68K(fx68k) - DLWORDSPER_CELL) % DLWORDSPER_QUAD);
} /*if end */
else
new68k = freestackblock(size, (StackWord *)CURRENTFX, -1); /* No align */
if (new68k == 0) return (0); /* No more space for STACK */
/* blt(dest,source,size) */
blt(new68k, (((DLword *)fx68k) - DLWORDSPER_CELL), size);
((Bframe *)new68k)->residual = T;
new68k = new68k + DLWORDSPER_CELL; /* now NEW points to the FX */
((FX *)new68k)->nextblock = (StkOffset_from_68K(new68k) + size) - DLWORDSPER_CELL;
retbf68k = (Bframe *)Addr68k_from_StkOffset(GETBLINK(fx68k));
/* Set true BFptr,not the residual */
SETBLINK(new68k, GETBLINK(fx68k));
((FX *)new68k)->usecount = 0;
CHECK_BF(retbf68k);
#ifdef BIGVM
if (nametbl_on_stk) ((FX *)new68k)->nametable += (((UNSIGNED)new68k - (UNSIGNED)fx68k) >> 1);
#else
if (nametbl_on_stk) ((FX *)new68k)->lonametable += (((UNSIGNED)new68k - (UNSIGNED)fx68k) >> 1);
#endif
/* increment use count of basic frame of returnee because
we made another FX which points to it */
retbf68k->usecnt++;
SET_FASTP_NIL(fx68k);
/* increment use count of CLINK of returnee
because we made a copy of returnee */
incusecount68k((FX *)Addr68k_from_StkOffset(GETCLINK(fx68k)));
if (GETCLINK(fx68k) != GETALINK(fx68k)) {
incusecount68k((FX *)Addr68k_from_StkOffset(GETALINK(fx68k)));
}
decusecount68k(fx68k); /* if usecon==0 -> FSB */
SETACLINK(CURRENTFX, StkOffset_from_68K(new68k));
CHECK_FX((FX *)new68k);
CHECK_FX(CURRENTFX);
#ifdef STACKCHECK
stack_check(0);
#endif
#ifdef FLIPCURSOR
flip_cursorbar(5);
#endif
return ((FX *)new68k);
} /* make_FXcopy end */
/********************************************************************/
/*
Func Name : slowreturn()
Edited by Takeshi Shimizu
DATE: 10-MAY-88
RET VAL : If 0 success
If 1 NO STACK SPACE->uraid-> HARDRESET
NBriggs, Aug 11 2020: I see no return (1) case!
*/
/********************************************************************/
int slowreturn(void) {
register DLword *next68k;
register DLword *freeptr;
register Bframe *currentBF;
register FX *returnFX;
S_CHECK(SLOWP(CURRENTFX), "CURRENTFX not SLOWP");
/* Get returnee's FX from CURRENTFX->alink , It's SLOWP case */
returnFX = (FX *)Addr68k_from_StkOffset(CURRENTFX->alink - 11);
if ((CURRENTFX->alink & 0xFFFE) != CURRENTFX->clink) { /* ALINK != CLINK */
#ifdef STACKCHECK
printf("A!=C\n");
#endif
/* return to CLINK fx */
SETALINK(CURRENTFX, CURRENTFX->clink);
decusecount68k(returnFX);
returnFX = (FX *)Addr68k_from_StkOffset(CURRENTFX->clink - FRAMESIZE);
}
if (returnFX->usecount != 0) { /* COPY returnee's FX */
#ifdef STACKCHECK
printf("returnFX->usecount !=0\n");
#endif
MAKE_FXCOPY(returnFX); /* smashes returnFX */
}
retry: /* this is retry entry after MAKE_FXCOPY etc */
next68k = Addr68k_from_StkOffset(returnFX->nextblock);
currentBF = (Bframe *)Addr68k_from_StkOffset(CURRENTFX->blink);
if (GETWORD(next68k) == STK_FSB_WORD) {
another:
freeptr = ((DLword *)CURRENTFX) - 2;
if (BFRAMEPTR(freeptr)->residual) {
if (BFRAMEPTR(currentBF)->usecnt == 0) {
/* make FREEBLOCK for real BF */
GETWORD(IVar) = STK_FSB_WORD;
GETWORD(IVar + 1) = (((UNSIGNED)currentBF - (UNSIGNED)IVar) >> 1) + 2;
if (0 == GETWORD(IVar + 1)) error("creating 0-len block");
} else
BFRAMEPTR(currentBF)->usecnt--;
} else
freeptr = IVar; /* reset free ptr: not residual case */
/* free FX + BF(dummy or real) */
GETWORD(freeptr) = STK_FSB_WORD;
GETWORD(freeptr + 1) = ((UNSIGNED)EndSTKP - (UNSIGNED)freeptr) >> 1;
if (0 == GETWORD(freeptr + 1)) error("creating 0-len block");
S_CHECK(EndSTKP >= freeptr, "EndSTKP < freeptr!");
S_CHECK(FSB_size(freeptr) >= MINEXTRASTACKWORDS,
"free block < min size, after deciding it fits.");
PVar = ((DLword *)returnFX) + FRAMESIZE;
/* Now right CURRENTFX(PVar) is set */
if (GETWORD(next68k) != STK_FSB_WORD) error("OP_return: MP9316");
freeptr = next68k;
while (GETWORD(freeptr) == STK_FSB_WORD) EndSTKP = freeptr = freeptr + GETWORD(freeptr + 1);
if (CURRENTFX->incall) { /* this frame is Interrupted */
error("Stack error: INCALL bit found in returnee frame");
} else {
if (CURRENTFX->nopush) {
CURRENTFX->nopush = NIL;
CurrentStackPTR = next68k - 2;
TopOfStack = *((LispPTR *)CurrentStackPTR);
CurrentStackPTR -= 2;
} else
CurrentStackPTR = next68k - 2;
S_CHECK(EndSTKP >= freeptr, "EndSTKP < freeptr");
FastRetCALL;
#ifdef LISPTRACE
printf("TRACE: return from ");
print(fnobj->framename);
printf(" :<= ");
print(TopOfStack);
printf("\n");
#endif
return (0); /* normal return */
}
} /* FSB end */
else if (next68k != IVar) {
#ifdef STACKCHECK
printf("next68k != IVar and not FSB\n");
#endif
MAKE_FXCOPY(returnFX); /* smashes returnFX */
goto retry;
} else if (BFRAMEPTR(currentBF)->usecnt != 0) {
#ifdef STACKCHECK
printf("currentBF->usecnt != 0");
#endif
MAKE_FXCOPY(returnFX); /* smashes returnFX */
goto retry;
} else {
if ((next68k == IVar) || (BFRAMEPTR(currentBF)->usecnt == 0))
goto another;
else
error("Shouldn't");
}
error("Control reached end of slowreturn()!");
return (NIL); /* NOT REACHED */
} /* slowreturn end */
#define MAXSAFEUSECOUNT 200
void incusecount68k(FX *fx68k) {
StackWord *scanptr68k;
if (FX_INVALIDP(fx68k)) return;
CHECK_FX(fx68k);
if ((++(fx68k->usecount)) > MAXSAFEUSECOUNT)
error("MP9324:Stack frame use count maximum exceeded");
scanptr68k = (StackWord *)Addr68k_from_StkOffset(fx68k->nextblock);
switch (STKWORD(scanptr68k)->flags) {
case STK_NOTFLG:
while (STKWORD(scanptr68k)->flags != STK_BF)
scanptr68k = (StackWord *)(((DLword *)scanptr68k) + DLWORDSPER_CELL);
break;
case STK_BF: break;
default:
return;
/* break; */
} /* switch end */
/* DEBUG */
S_CHECK(
(((Bframe *)scanptr68k)->residual == T) || (((Bframe *)scanptr68k)->ivar == fx68k->nextblock),
"BF not residual, and IVER /= nextblock of prior frame");
scanptr68k = (StackWord *)(((DLword *)scanptr68k) + DLWORDSPER_CELL);
if (STKWORD(scanptr68k)->flags == STK_FX) {
CHECK_FX((FX *)scanptr68k);
SET_FASTP_NIL(scanptr68k);
}
} /* incusecount68k end */
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