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Add ftwotox emulation, by using the fscale emulation routine (preload

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destination register bit pattern with 1.0), which automatically provides
corner case handling.
Missing ftwotox emulation originally reported by Norman Mackenzie in PR 4237,
but he proposed a different implementation.
This commit is contained in:
is 1997-11-02 22:02:46 +00:00
parent 8dbb87fe86
commit 2ee51585ba
2 changed files with 18 additions and 2 deletions
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9
sys/arch/m68k/fpe/fpu_emulate.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: fpu_emulate.c,v 1.17 1997/07/20 12:39:17 is Exp $ */
/* $NetBSD: fpu_emulate.c,v 1.18 1997/11/02 22:02:46 is Exp $ */
/*
* Copyright (c) 1995 Gordon W. Ross
@ -212,6 +212,11 @@ fpu_emulate(frame, fpf)
if (fpu_debug_level & DL_INSN)
printf(" fpu_emulate: fscale\n");
sig = fpu_emul_fscale(&fe, &insn);
} else if ((word & 0xa07f) == 0x11) {
/* ftwotox */
if (fpu_debug_level & DL_INSN)
printf(" fpu_emulate: ftwotox\n");
sig = fpu_emul_fscale(&fe, &insn);
} else {
if (fpu_debug_level & DL_INSN)
printf(" fpu_emulte: other type0\n");
@ -801,9 +806,11 @@ fpu_emul_arith(fe, insn)
res = fpu_etox(fe);
break;
#if 0 /* handled by fscale now */
case 0x11: /* ftwotox */
res = fpu_twotox(fe);
break;
#endif
case 0x12: /* ftentox */
res = fpu_tentox(fe);

11
sys/arch/m68k/fpe/fpu_fscale.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: fpu_fscale.c,v 1.7 1997/10/09 19:19:01 is Exp $ */
/* $NetBSD: fpu_fscale.c,v 1.8 1997/11/02 22:02:47 is Exp $ */
/*
* Copyright (c) 1995 Ken Nakata
@ -181,6 +181,15 @@ fpu_emul_fscale(fe, insn)
/* it's barbaric but we're going to operate directly on
* the dst operand's bit pattern */
if ((word1 & 0x7f) == 0x11) {
/* ftwotox: preload reg with 1.0 */
fpregs[regnum * 3 + 0] = 0x3fff0000;
fpregs[regnum * 3 + 1] = 0x80000000;
fpregs[regnum * 3 + 2] = 0x00000000;
fe->fe_f2.fp_class = FPC_NUM;
}
sign = fpregs[regnum * 3] & 0x80000000;
exp = (fpregs[regnum * 3] & 0x7fff0000) >> 16;
m0 = fpregs[regnum * 3 + 1];