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2002-06-07 Chris Demetriou <cgd@broadcom.com>

Browse source 
Ed Satterthwaite  <ehs@broadcom.com>

        * cp1.c: Fix more comment spelling and formatting.
        (value_fcr, store_fcr): Use fenr_FS rather than hard-coding value.
        (denorm_mode): New function.
        (fpu_unary, fpu_binary): Round results after operation, collect
        status from rounding operations, and update the FCSR.
        (convert): Collect status from integer conversions and rounding
        operations, and update the FCSR.  Adjust NaN values that result
        from conversions.  Convert to use sim_io_eprintf rather than
        fprintf, and remove some debugging code.
        * cp1.h (fenr_FS): New define.
This commit is contained in:
Chris Demetriou 2002-06-07 22:55:49 +00:00
parent 85b5171940
commit 52714ff9ee
3 changed files with 93 additions and 43 deletions
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14
sim/mips/ChangeLog
View file

@ -1,3 +1,17 @@
2002-06-07 Chris Demetriou <cgd@broadcom.com>
Ed Satterthwaite <ehs@broadcom.com>
* cp1.c: Fix more comment spelling and formatting.
(value_fcr, store_fcr): Use fenr_FS rather than hard-coding value.
(denorm_mode): New function.
(fpu_unary, fpu_binary): Round results after operation, collect
status from rounding operations, and update the FCSR.
(convert): Collect status from integer conversions and rounding
operations, and update the FCSR. Adjust NaN values that result
from conversions. Convert to use sim_io_eprintf rather than
fprintf, and remove some debugging code.
* cp1.h (fenr_FS): New define.
2002-06-07 Chris Demetriou <cgd@broadcom.com>
* cp1.c (convert): Remove unusable debugging code, and move MIPS

121
sim/mips/cp1.c
View file

@ -73,7 +73,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
i = 63bits = integer
*/
/* Explicit QNaN values used when value required: */
/* Explicit QNaN values. */
#define FPQNaN_SINGLE (0x7FBFFFFF)
#define FPQNaN_WORD (0x7FFFFFFF)
#define FPQNaN_DOUBLE (UNSIGNED64 (0x7FF7FFFFFFFFFFFF))
@ -93,7 +93,7 @@ value_fpr (sim_cpu *cpu,
uword64 value = 0;
int err = 0;
/* Treat unused register values, as fixed-point 64bit values: */
/* Treat unused register values, as fixed-point 64bit values. */
if ((fmt == fmt_uninterpreted) || (fmt == fmt_unknown))
{
#if 1
@ -105,7 +105,7 @@ value_fpr (sim_cpu *cpu,
#endif
}
/* For values not yet accessed, set to the desired format: */
/* For values not yet accessed, set to the desired format. */
if (FPR_STATE[fpr] == fmt_uninterpreted)
{
FPR_STATE[fpr] = fmt;
@ -168,7 +168,7 @@ value_fpr (sim_cpu *cpu,
case fmt_long:
if ((fpr & 1) == 0)
{
/* Even registers numbers only. */
/* Even register numbers only. */
#ifdef DEBUG
printf ("DBG: ValueFPR: FGR[%d] = %s, FGR[%d] = %s\n",
fpr + 1, pr_uword64 ((uword64) FGR[fpr+1]),
@ -299,7 +299,7 @@ store_fpr (sim_cpu *cpu,
}
/* CP1 control/status registers */
/* CP1 control/status register access functions. */
void
test_fcsr (sim_cpu *cpu,
@ -324,22 +324,22 @@ value_fcr(sim_cpu *cpu,
switch (fcr)
{
case 0: /* FP Implementation and Revision Register */
case 0: /* FP Implementation and Revision Register. */
value = FCR0;
break;
case 25: /* FP Condition Codes Register */
case 25: /* FP Condition Codes Register (derived from FCSR). */
value = (FCR31 & fcsr_FCC_mask) >> fcsr_FCC_shift;
value = (value & 0x1) | (value >> 1); /* close FCC gap */
value = (value & 0x1) | (value >> 1); /* Close FCC gap. */
break;
case 26: /* FP Exceptions Register */
case 26: /* FP Exceptions Register (derived from FCSR). */
value = FCR31 & (fcsr_CAUSE_mask | fcsr_FLAGS_mask);
break;
case 28: /* FP Enables Register */
case 28: /* FP Enables Register (derived from FCSR). */
value = FCR31 & (fcsr_ENABLES_mask | fcsr_RM_mask);
if (FCR31 & fcsr_FS)
value |= 0x4; /* nonstandard FS bit */
if ((FCR31 & fcsr_FS) != 0)
value |= fenr_FS;
break;
case 31: /* FP Control/Status Register */
case 31: /* FP Control/Status Register (FCSR). */
value = FCR31 & ~fcsr_ZERO_mask;
break;
}
@ -358,18 +358,18 @@ store_fcr(sim_cpu *cpu,
v = VL4_8(value);
switch (fcr)
{
case 25: /* FP Condition Codes Register */
v = (v << 1) | (v & 0x1); /* adjust for FCC gap */
case 25: /* FP Condition Codes Register (stored into FCSR). */
v = (v << 1) | (v & 0x1); /* Adjust for FCC gap. */
FCR31 &= ~fcsr_FCC_mask;
FCR31 |= ((v << fcsr_FCC_shift) & fcsr_FCC_mask);
break;
case 26: /* FP Exceptions Register */
case 26: /* FP Exceptions Register (stored into FCSR). */
FCR31 &= ~(fcsr_CAUSE_mask | fcsr_FLAGS_mask);
FCR31 |= (v & (fcsr_CAUSE_mask | fcsr_FLAGS_mask));
test_fcsr(cpu, cia);
break;
case 28: /* FP Enables Register */
if (v & 0x4) /* nonstandard FS bit */
case 28: /* FP Enables Register (stored into FCSR). */
if ((v & fenr_FS) != 0)
v |= fcsr_FS;
else
v &= ~fcsr_FS;
@ -377,7 +377,7 @@ store_fcr(sim_cpu *cpu,
FCR31 |= (v & (fcsr_FS | fcsr_ENABLES_mask | fcsr_RM_mask));
test_fcsr(cpu, cia);
break;
case 31: /* FP Control/Status Register */
case 31: /* FP Control/Status Register (FCSR). */
FCR31 = v & ~fcsr_ZERO_mask;
test_fcsr(cpu, cia);
break;
@ -414,7 +414,7 @@ update_fcsr (sim_cpu *cpu,
if (status & sim_fpu_status_inexact)
cause |= (1 << IR);
#if 0 /* Not yet. */
/* Implicit clearing of other bits by unimplemented done by callers. */
/* Implicit clearing of other bits by unimplemented done by callers. */
if (status & sim_fpu_status_unimplemented)
cause |= (1 << UO);
#endif
@ -436,22 +436,22 @@ rounding_mode(int rm)
case FP_RM_NEAREST:
/* Round result to nearest representable value. When two
representable values are equally near, round to the value
that has a least significant bit of zero (i.e. is even). */
that has a least significant bit of zero (i.e. is even). */
round = sim_fpu_round_near;
break;
case FP_RM_TOZERO:
/* Round result to the value closest to, and not greater in
magnitude than, the result. */
magnitude than, the result. */
round = sim_fpu_round_zero;
break;
case FP_RM_TOPINF:
/* Round result to the value closest to, and not less than,
the result. */
the result. */
round = sim_fpu_round_up;
break;
case FP_RM_TOMINF:
/* Round result to the value closest to, and not greater than,
the result. */
the result. */
round = sim_fpu_round_down;
break;
default:
@ -462,6 +462,23 @@ rounding_mode(int rm)
return round;
}
/* When the FS bit is set, MIPS processors return zero for
denormalized results and optionally replace denormalized inputs
with zero. When FS is clear, some implementation trap on input
and/or output, while other perform the operation in hardware. */
static sim_fpu_denorm
denorm_mode(sim_cpu *cpu)
{
sim_fpu_denorm denorm;
/* XXX: FIXME: Eventually should be CPU model dependent. */
if (GETFS())
denorm = sim_fpu_denorm_zero;
else
denorm = 0;
return denorm;
}
/* Comparison operations. */
@ -536,7 +553,9 @@ fp_cmp(sim_cpu *cpu,
{
sim_fpu_status status = 0;
/* The format type should already have been checked: */
/* The format type should already have been checked. The FCSR is
updated before the condition codes so that any exceptions will
be signalled before the condition codes are changed. */
switch (fmt)
{
case fmt_single:
@ -566,6 +585,9 @@ fp_unary(sim_cpu *cpu,
{
sim_fpu wop;
sim_fpu ans;
sim_fpu_round round = rounding_mode (GETRM());
sim_fpu_denorm denorm = denorm_mode (cpu);
sim_fpu_status status = 0;
unsigned64 result = 0;
/* The format type has already been checked: */
@ -575,7 +597,8 @@ fp_unary(sim_cpu *cpu,
{
unsigned32 res;
sim_fpu_32to (&wop, op);
(*sim_fpu_op) (&ans, &wop);
status |= (*sim_fpu_op) (&ans, &wop);
status |= sim_fpu_round_32 (&ans, round, denorm);
sim_fpu_to32 (&res, &ans);
result = res;
break;
@ -584,7 +607,8 @@ fp_unary(sim_cpu *cpu,
{
unsigned64 res;
sim_fpu_64to (&wop, op);
(*sim_fpu_op) (&ans, &wop);
status |= (*sim_fpu_op) (&ans, &wop);
status |= sim_fpu_round_64 (&ans, round, denorm);
sim_fpu_to64 (&res, &ans);
result = res;
break;
@ -594,6 +618,7 @@ fp_unary(sim_cpu *cpu,
abort ();
}
update_fcsr (cpu, cia, status);
return result;
}
@ -608,6 +633,9 @@ fp_binary(sim_cpu *cpu,
sim_fpu wop1;
sim_fpu wop2;
sim_fpu ans;
sim_fpu_round round = rounding_mode (GETRM());
sim_fpu_denorm denorm = denorm_mode (cpu);
sim_fpu_status status = 0;
unsigned64 result = 0;
/* The format type has already been checked: */
@ -618,7 +646,8 @@ fp_binary(sim_cpu *cpu,
unsigned32 res;
sim_fpu_32to (&wop1, op1);
sim_fpu_32to (&wop2, op2);
(*sim_fpu_op) (&ans, &wop1, &wop2);
status |= (*sim_fpu_op) (&ans, &wop1, &wop2);
status |= sim_fpu_round_32 (&ans, round, denorm);
sim_fpu_to32 (&res, &ans);
result = res;
break;
@ -628,7 +657,8 @@ fp_binary(sim_cpu *cpu,
unsigned64 res;
sim_fpu_64to (&wop1, op1);
sim_fpu_64to (&wop2, op2);
(*sim_fpu_op) (&ans, &wop1, &wop2);
status |= (*sim_fpu_op) (&ans, &wop1, &wop2);
status |= sim_fpu_round_64 (&ans, round, denorm);
sim_fpu_to64 (&res, &ans);
result = res;
break;
@ -638,6 +668,7 @@ fp_binary(sim_cpu *cpu,
abort ();
}
update_fcsr (cpu, cia, status);
return result;
}
@ -731,8 +762,10 @@ convert (sim_cpu *cpu,
{
sim_fpu wop;
sim_fpu_round round = rounding_mode (rm);
sim_fpu_denorm denorm = denorm_mode (cpu);
unsigned32 result32;
unsigned64 result64;
sim_fpu_status status = 0;
/* Convert the input to sim_fpu internal format */
switch (from)
@ -744,13 +777,13 @@ convert (sim_cpu *cpu,
sim_fpu_32to (&wop, op);
break;
case fmt_word:
sim_fpu_i32to (&wop, op, round);
status = sim_fpu_i32to (&wop, op, round);
break;
case fmt_long:
sim_fpu_i64to (&wop, op, round);
status = sim_fpu_i64to (&wop, op, round);
break;
default:
fprintf (stderr, "Bad switch\n");
sim_io_eprintf (SD, "Bad switch\n");
abort ();
}
@ -763,33 +796,35 @@ convert (sim_cpu *cpu,
switch (to)
{
case fmt_single:
sim_fpu_round_32 (&wop, round, 0);
status |= sim_fpu_round_32 (&wop, round, denorm);
/* For a NaN, normalize mantissa bits (cvt.s.d can't preserve them) */
if (sim_fpu_is_qnan (&wop))
wop = sim_fpu_qnan;
sim_fpu_to32 (&result32, &wop);
result64 = result32;
break;
case fmt_double:
sim_fpu_round_64 (&wop, round, 0);
status |= sim_fpu_round_64 (&wop, round, denorm);
/* For a NaN, normalize mantissa bits (make cvt.d.s consistent) */
if (sim_fpu_is_qnan (&wop))
wop = sim_fpu_qnan;
sim_fpu_to64 (&result64, &wop);
break;
case fmt_word:
sim_fpu_to32i (&result32, &wop, round);
status |= sim_fpu_to32i (&result32, &wop, round);
result64 = result32;
break;
case fmt_long:
sim_fpu_to64i (&result64, &wop, round);
status |= sim_fpu_to64i (&result64, &wop, round);
break;
default:
result64 = 0;
fprintf (stderr, "Bad switch\n");
sim_io_eprintf (SD, "Bad switch\n");
abort ();
}
#ifdef DEBUG
printf ("DBG: Convert: returning 0x%s (to format = %s)\n",
pr_addr (result64), fpu_format_name (to));
#endif /* DEBUG */
return (result64);
update_fcsr (cpu, cia, status);
return result64;
}
static const char *

1
sim/mips/cp1.h
View file

@ -40,6 +40,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
#define fcsr_RM_mask (0x00000003)
#define fcsr_RM_shift (0)
#define fenr_FS (0x00000004)
/* Macros to update and retrieve the FCSR condition-code bits. This
is complicated by the fact that there is a hole in the index range