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>
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@ -572,3 +572,8 @@ void HELPER(flog10)(CPUM68KState *env, FPReg *res, FPReg *val)
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{
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{
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res->d = floatx80_log10(val->d, &env->fp_status);
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res->d = floatx80_log10(val->d, &env->fp_status);
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}
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}
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void HELPER(flog2)(CPUM68KState *env, FPReg *res, FPReg *val)
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{
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res->d = floatx80_log2(val->d, &env->fp_status);
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}
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@ -71,6 +71,7 @@ DEF_HELPER_4(fscale, void, env, fp, fp, fp)
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DEF_HELPER_3(flognp1, void, env, fp, fp)
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DEF_HELPER_3(flognp1, void, env, fp, fp)
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DEF_HELPER_3(flogn, void, env, fp, fp)
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DEF_HELPER_3(flogn, void, env, fp, fp)
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DEF_HELPER_3(flog10, void, env, fp, fp)
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DEF_HELPER_3(flog10, void, env, fp, fp)
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DEF_HELPER_3(flog2, void, env, fp, fp)
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DEF_HELPER_3(mac_move, void, env, i32, i32)
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DEF_HELPER_3(mac_move, void, env, i32, i32)
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DEF_HELPER_3(macmulf, i64, env, i32, i32)
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DEF_HELPER_3(macmulf, i64, env, i32, i32)
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@ -715,3 +715,70 @@ floatx80 floatx80_log10(floatx80 a, float_status *status)
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return a;
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return a;
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}
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}
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/*----------------------------------------------------------------------------
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| Log base 2
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*----------------------------------------------------------------------------*/
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floatx80 floatx80_log2(floatx80 a, float_status *status)
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{
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flag aSign;
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int32_t aExp;
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uint64_t aSig;
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int8_t user_rnd_mode, user_rnd_prec;
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floatx80 fp0, fp1;
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aSig = extractFloatx80Frac(a);
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aExp = extractFloatx80Exp(a);
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aSign = extractFloatx80Sign(a);
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if (aExp == 0x7FFF) {
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if ((uint64_t) (aSig << 1)) {
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propagateFloatx80NaNOneArg(a, status);
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}
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if (aSign == 0) {
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return packFloatx80(0, floatx80_infinity.high,
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floatx80_infinity.low);
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}
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}
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if (aExp == 0) {
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if (aSig == 0) {
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float_raise(float_flag_divbyzero, status);
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return packFloatx80(1, floatx80_infinity.high,
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floatx80_infinity.low);
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}
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normalizeFloatx80Subnormal(aSig, &aExp, &aSig);
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}
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if (aSign) {
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float_raise(float_flag_invalid, status);
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return floatx80_default_nan(status);
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}
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user_rnd_mode = status->float_rounding_mode;
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user_rnd_prec = status->floatx80_rounding_precision;
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status->float_rounding_mode = float_round_nearest_even;
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status->floatx80_rounding_precision = 80;
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if (aSig == one_sig) { /* X is 2^k */
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status->float_rounding_mode = user_rnd_mode;
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status->floatx80_rounding_precision = user_rnd_prec;
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a = int32_to_floatx80(aExp - 0x3FFF, status);
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} else {
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fp0 = floatx80_logn(a, status);
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fp1 = packFloatx80(0, 0x3FFF, LIT64(0xB8AA3B295C17F0BC)); /* INV_L2 */
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status->float_rounding_mode = user_rnd_mode;
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status->floatx80_rounding_precision = user_rnd_prec;
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a = floatx80_mul(fp0, fp1, status); /* LOGN(X)*INV_L2 */
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}
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float_raise(float_flag_inexact, status);
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return a;
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}
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@ -30,4 +30,5 @@ floatx80 floatx80_move(floatx80 a, float_status *status);
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floatx80 floatx80_lognp1(floatx80 a, float_status *status);
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floatx80 floatx80_lognp1(floatx80 a, float_status *status);
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floatx80 floatx80_logn(floatx80 a, float_status *status);
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floatx80 floatx80_logn(floatx80 a, float_status *status);
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floatx80 floatx80_log10(floatx80 a, float_status *status);
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floatx80 floatx80_log10(floatx80 a, float_status *status);
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floatx80 floatx80_log2(floatx80 a, float_status *status);
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#endif
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#endif
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@ -5063,6 +5063,9 @@ DISAS_INSN(fpu)
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case 0x15: /* flog10 */
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case 0x15: /* flog10 */
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gen_helper_flog10(cpu_env, cpu_dest, cpu_src);
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gen_helper_flog10(cpu_env, cpu_dest, cpu_src);
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break;
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break;
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case 0x16: /* flog2 */
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gen_helper_flog2(cpu_env, cpu_dest, cpu_src);
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break;
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case 0x18: /* fabs */
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case 0x18: /* fabs */
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gen_helper_fabs(cpu_env, cpu_dest, cpu_src);
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gen_helper_fabs(cpu_env, cpu_dest, cpu_src);
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break;
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break;
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