On 13 March 2018 at 15:59, Laurent Vivier <laur...@vivier.eu> wrote:
> Using a local m68k floatx80_sin()
> [copied from previous:
> Written by Andreas Grabher for Previous, NeXT Computer Emulator.]
>
> Signed-off-by: Laurent Vivier <laur...@vivier.eu>
> Message-Id: <20180312202728.23790-3-laur...@vivier.eu>
> ---
> target/m68k/fpu_helper.c | 5 +
> target/m68k/helper.h | 1 +
> target/m68k/softfloat.c | 247
> +++++++++++++++++++++++++++++++++++++++++++++++
> target/m68k/softfloat.h | 1 +
> target/m68k/translate.c | 3 +
> 5 files changed, 257 insertions(+)
>
> diff --git a/target/m68k/fpu_helper.c b/target/m68k/fpu_helper.c
> index c41115ea05..a6cfb4db1a 100644
> --- a/target/m68k/fpu_helper.c
> +++ b/target/m68k/fpu_helper.c
> @@ -597,3 +597,8 @@ void HELPER(ftan)(CPUM68KState *env, FPReg *res, FPReg
> *val)
> {
> res->d = floatx80_tan(val->d, &env->fp_status);
> }
> +
> +void HELPER(fsin)(CPUM68KState *env, FPReg *res, FPReg *val)
> +{
> + res->d = floatx80_sin(val->d, &env->fp_status);
> +}
> diff --git a/target/m68k/helper.h b/target/m68k/helper.h
> index af9480fe49..6d8bfaab64 100644
> --- a/target/m68k/helper.h
> +++ b/target/m68k/helper.h
> @@ -76,6 +76,7 @@ DEF_HELPER_3(fetox, void, env, fp, fp)
> DEF_HELPER_3(ftwotox, void, env, fp, fp)
> DEF_HELPER_3(ftentox, void, env, fp, fp)
> DEF_HELPER_3(ftan, void, env, fp, fp)
> +DEF_HELPER_3(fsin, void, env, fp, fp)
>
> DEF_HELPER_3(mac_move, void, env, i32, i32)
> DEF_HELPER_3(macmulf, i64, env, i32, i32)
> diff --git a/target/m68k/softfloat.c b/target/m68k/softfloat.c
> index 488dbc522b..6fb9665336 100644
> --- a/target/m68k/softfloat.c
> +++ b/target/m68k/softfloat.c
> @@ -1476,3 +1476,250 @@ floatx80 floatx80_tan(floatx80 a, float_status
> *status)
> }
> }
> }
> +
> +/*----------------------------------------------------------------------------
> + | Sine
> +
> *----------------------------------------------------------------------------*/
> +
> +floatx80 floatx80_sin(floatx80 a, float_status *status)
> +{
Hi; Coverity (CID1390617) points out that there is dead code in this function:
> + flag aSign, xSign;
> + int32_t aExp, xExp;
> + uint64_t aSig, xSig;
> +
> + int8_t user_rnd_mode, user_rnd_prec;
> +
> + int32_t compact, l, n, j;
> + floatx80 fp0, fp1, fp2, fp3, fp4, fp5, x, invtwopi, twopi1, twopi2;
> + float32 posneg1, twoto63;
> + flag adjn, endflag;
> +
> + aSig = extractFloatx80Frac(a);
> + aExp = extractFloatx80Exp(a);
> + aSign = extractFloatx80Sign(a);
> +
> + if (aExp == 0x7FFF) {
> + if ((uint64_t) (aSig << 1)) {
> + return propagateFloatx80NaNOneArg(a, status);
> + }
> + float_raise(float_flag_invalid, status);
> + return floatx80_default_nan(status);
> + }
> +
> + if (aExp == 0 && aSig == 0) {
> + return packFloatx80(aSign, 0, 0);
> + }
> +
> + adjn = 0;
Here we set adjn == 0...
> +
> + user_rnd_mode = status->float_rounding_mode;
> + user_rnd_prec = status->floatx80_rounding_precision;
> + status->float_rounding_mode = float_round_nearest_even;
> + status->floatx80_rounding_precision = 80;
> +
> + compact = floatx80_make_compact(aExp, aSig);
> +
> + fp0 = a;
> +
> + if (compact < 0x3FD78000 || compact > 0x4004BC7E) {
> + /* 2^(-40) > |X| > 15 PI */
> + if (compact > 0x3FFF8000) { /* |X| >= 15 PI */
> + /* REDUCEX */
> + fp1 = packFloatx80(0, 0, 0);
> + if (compact == 0x7FFEFFFF) {
> + twopi1 = packFloatx80(aSign ^ 1, 0x7FFE,
> + LIT64(0xC90FDAA200000000));
> + twopi2 = packFloatx80(aSign ^ 1, 0x7FDC,
> + LIT64(0x85A308D300000000));
> + fp0 = floatx80_add(fp0, twopi1, status);
> + fp1 = fp0;
> + fp0 = floatx80_add(fp0, twopi2, status);
> + fp1 = floatx80_sub(fp1, fp0, status);
> + fp1 = floatx80_add(fp1, twopi2, status);
> + }
> + loop:
> + xSign = extractFloatx80Sign(fp0);
> + xExp = extractFloatx80Exp(fp0);
> + xExp -= 0x3FFF;
> + if (xExp <= 28) {
> + l = 0;
> + endflag = 1;
> + } else {
> + l = xExp - 27;
> + endflag = 0;
> + }
> + invtwopi = packFloatx80(0, 0x3FFE - l,
> + LIT64(0xA2F9836E4E44152A)); /* INVTWOPI
> */
> + twopi1 = packFloatx80(0, 0x3FFF + l, LIT64(0xC90FDAA200000000));
> + twopi2 = packFloatx80(0, 0x3FDD + l, LIT64(0x85A308D300000000));
> +
> + /* SIGN(INARG)*2^63 IN SGL */
> + twoto63 = packFloat32(xSign, 0xBE, 0);
> +
> + fp2 = floatx80_mul(fp0, invtwopi, status);
> + fp2 = floatx80_add(fp2, float32_to_floatx80(twoto63, status),
> + status); /* THE FRACT PART OF FP2 IS ROUNDED
> */
> + fp2 = floatx80_sub(fp2, float32_to_floatx80(twoto63, status),
> + status); /* FP2 is N */
> + fp4 = floatx80_mul(twopi1, fp2, status); /* W = N*P1 */
> + fp5 = floatx80_mul(twopi2, fp2, status); /* w = N*P2 */
> + fp3 = floatx80_add(fp4, fp5, status); /* FP3 is P */
> + fp4 = floatx80_sub(fp4, fp3, status); /* W-P */
> + fp0 = floatx80_sub(fp0, fp3, status); /* FP0 is A := R - P */
> + fp4 = floatx80_add(fp4, fp5, status); /* FP4 is p = (W-P)+w */
> + fp3 = fp0; /* FP3 is A */
> + fp1 = floatx80_sub(fp1, fp4, status); /* FP1 is a := r - p */
> + fp0 = floatx80_add(fp0, fp1, status); /* FP0 is R := A+a */
> +
> + if (endflag > 0) {
> + n = floatx80_to_int32(fp2, status);
> + goto sincont;
> + }
> + fp3 = floatx80_sub(fp3, fp0, status); /* A-R */
> + fp1 = floatx80_add(fp1, fp3, status); /* FP1 is r := (A-R)+a */
> + goto loop;
> + } else {
> + /* SINSM */
> + fp0 = float32_to_floatx80(make_float32(0x3F800000),
> + status); /* 1 */
> +
> + status->float_rounding_mode = user_rnd_mode;
> + status->floatx80_rounding_precision = user_rnd_prec;
> +
> + if (adjn) {
...and we never change it before here, so this branch of this 'if'
is dead code.
> + /* COSTINY */
> + a = floatx80_sub(fp0, float32_to_floatx80(
> + make_float32(0x00800000), status), status);
> + } else {
> + /* SINTINY */
> + a = floatx80_move(a, status);
> + }
> + float_raise(float_flag_inexact, status);
> +
> + return a;
> + }
Similarly in floatx80_cos(), we set adjn = 1 at the top of
the function, and then later test it.
Should these two functions be sharing code? They do look
rather similar...
thanks
-- PMM
