diff options
author | Laurent Vivier <laurent@vivier.eu> | 2018-03-05 21:39:07 +0100 |
---|---|---|
committer | Laurent Vivier <laurent@vivier.eu> | 2018-03-09 15:50:38 +0100 |
commit | 67b453ed73fe65949c24e6ca2b43f6816a89a301 (patch) | |
tree | 29dedbbff941898a4ec0f97422ff2b8e28377505 /target/m68k | |
parent | 248efb66fb88bc17c04a0d0f09a3539a43c80769 (diff) |
target/m68k: implement flog2
Using a local m68k floatx80_log2()
[copied from previous:
Written by Andreas Grabher for Previous, NeXT Computer Emulator.]
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20180305203910.10391-6-laurent@vivier.eu>
Diffstat (limited to 'target/m68k')
-rw-r--r-- | target/m68k/fpu_helper.c | 5 | ||||
-rw-r--r-- | target/m68k/helper.h | 1 | ||||
-rw-r--r-- | target/m68k/softfloat.c | 67 | ||||
-rw-r--r-- | target/m68k/softfloat.h | 1 | ||||
-rw-r--r-- | target/m68k/translate.c | 3 |
5 files changed, 77 insertions, 0 deletions
diff --git a/target/m68k/fpu_helper.c b/target/m68k/fpu_helper.c index 2628534136..97a4501126 100644 --- a/target/m68k/fpu_helper.c +++ b/target/m68k/fpu_helper.c @@ -572,3 +572,8 @@ void HELPER(flog10)(CPUM68KState *env, FPReg *res, FPReg *val) { res->d = floatx80_log10(val->d, &env->fp_status); } + +void HELPER(flog2)(CPUM68KState *env, FPReg *res, FPReg *val) +{ + res->d = floatx80_log2(val->d, &env->fp_status); +} diff --git a/target/m68k/helper.h b/target/m68k/helper.h index d1f38f260f..15f63b353f 100644 --- a/target/m68k/helper.h +++ b/target/m68k/helper.h @@ -71,6 +71,7 @@ DEF_HELPER_4(fscale, void, env, fp, fp, fp) DEF_HELPER_3(flognp1, void, env, fp, fp) DEF_HELPER_3(flogn, void, env, fp, fp) DEF_HELPER_3(flog10, void, env, fp, fp) +DEF_HELPER_3(flog2, 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 22fd7f6341..9fa6d6fd05 100644 --- a/target/m68k/softfloat.c +++ b/target/m68k/softfloat.c @@ -715,3 +715,70 @@ floatx80 floatx80_log10(floatx80 a, float_status *status) return a; } + +/*---------------------------------------------------------------------------- + | Log base 2 + *----------------------------------------------------------------------------*/ + +floatx80 floatx80_log2(floatx80 a, float_status *status) +{ + flag aSign; + int32_t aExp; + uint64_t aSig; + + int8_t user_rnd_mode, user_rnd_prec; + + floatx80 fp0, fp1; + + aSig = extractFloatx80Frac(a); + aExp = extractFloatx80Exp(a); + aSign = extractFloatx80Sign(a); + + if (aExp == 0x7FFF) { + if ((uint64_t) (aSig << 1)) { + propagateFloatx80NaNOneArg(a, status); + } + if (aSign == 0) { + return packFloatx80(0, floatx80_infinity.high, + floatx80_infinity.low); + } + } + + if (aExp == 0) { + if (aSig == 0) { + float_raise(float_flag_divbyzero, status); + return packFloatx80(1, floatx80_infinity.high, + floatx80_infinity.low); + } + normalizeFloatx80Subnormal(aSig, &aExp, &aSig); + } + + if (aSign) { + float_raise(float_flag_invalid, status); + return floatx80_default_nan(status); + } + + 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; + + if (aSig == one_sig) { /* X is 2^k */ + status->float_rounding_mode = user_rnd_mode; + status->floatx80_rounding_precision = user_rnd_prec; + + a = int32_to_floatx80(aExp - 0x3FFF, status); + } else { + fp0 = floatx80_logn(a, status); + fp1 = packFloatx80(0, 0x3FFF, LIT64(0xB8AA3B295C17F0BC)); /* INV_L2 */ + + status->float_rounding_mode = user_rnd_mode; + status->floatx80_rounding_precision = user_rnd_prec; + + a = floatx80_mul(fp0, fp1, status); /* LOGN(X)*INV_L2 */ + } + + float_raise(float_flag_inexact, status); + + return a; +} diff --git a/target/m68k/softfloat.h b/target/m68k/softfloat.h index ac29e76189..c0b77cf01b 100644 --- a/target/m68k/softfloat.h +++ b/target/m68k/softfloat.h @@ -30,4 +30,5 @@ floatx80 floatx80_move(floatx80 a, float_status *status); floatx80 floatx80_lognp1(floatx80 a, float_status *status); floatx80 floatx80_logn(floatx80 a, float_status *status); floatx80 floatx80_log10(floatx80 a, float_status *status); +floatx80 floatx80_log2(floatx80 a, float_status *status); #endif diff --git a/target/m68k/translate.c b/target/m68k/translate.c index f1130df314..189b23d38d 100644 --- a/target/m68k/translate.c +++ b/target/m68k/translate.c @@ -5063,6 +5063,9 @@ DISAS_INSN(fpu) case 0x15: /* flog10 */ gen_helper_flog10(cpu_env, cpu_dest, cpu_src); break; + case 0x16: /* flog2 */ + gen_helper_flog2(cpu_env, cpu_dest, cpu_src); + break; case 0x18: /* fabs */ gen_helper_fabs(cpu_env, cpu_dest, cpu_src); break; |