aboutsummaryrefslogtreecommitdiff
path: root/target/m68k/softfloat.c
diff options
context:
space:
mode:
authorLaurent Vivier <laurent@vivier.eu>2018-03-05 21:39:10 +0100
committerLaurent Vivier <laurent@vivier.eu>2018-03-09 15:50:38 +0100
commit6c25be6e30bda0e470f8f0b6b93d53a6efe469e8 (patch)
tree161a08bb98957a85ec8941141ccef0f1925558e7 /target/m68k/softfloat.c
parent068f161536d9a28a5bc482f3de9c387b2fe5908d (diff)
downloadqemu-6c25be6e30bda0e470f8f0b6b93d53a6efe469e8.zip
qemu-6c25be6e30bda0e470f8f0b6b93d53a6efe469e8.tar.gz
qemu-6c25be6e30bda0e470f8f0b6b93d53a6efe469e8.tar.bz2
target/m68k: implement ftentox
Using a local m68k floatx80_tentox() [copied from previous: Written by Andreas Grabher for Previous, NeXT Computer Emulator.] Signed-off-by: Laurent Vivier <laurent@vivier.eu> Message-Id: <20180305203910.10391-9-laurent@vivier.eu>
Diffstat (limited to 'target/m68k/softfloat.c')
-rw-r--r--target/m68k/softfloat.c153
1 files changed, 153 insertions, 0 deletions
diff --git a/target/m68k/softfloat.c b/target/m68k/softfloat.c
index cfff30d..4bd5b9e 100644
--- a/target/m68k/softfloat.c
+++ b/target/m68k/softfloat.c
@@ -1113,3 +1113,156 @@ floatx80 floatx80_twotox(floatx80 a, float_status *status)
return a;
}
}
+
+/*----------------------------------------------------------------------------
+ | 10 to x
+ *----------------------------------------------------------------------------*/
+
+floatx80 floatx80_tentox(floatx80 a, float_status *status)
+{
+ flag aSign;
+ int32_t aExp;
+ uint64_t aSig;
+
+ int8_t user_rnd_mode, user_rnd_prec;
+
+ int32_t compact, n, j, l, m, m1;
+ floatx80 fp0, fp1, fp2, fp3, adjfact, fact1, fact2;
+
+ aSig = extractFloatx80Frac(a);
+ aExp = extractFloatx80Exp(a);
+ aSign = extractFloatx80Sign(a);
+
+ if (aExp == 0x7FFF) {
+ if ((uint64_t) (aSig << 1)) {
+ return propagateFloatx80NaNOneArg(a, status);
+ }
+ if (aSign) {
+ return packFloatx80(0, 0, 0);
+ }
+ return packFloatx80(0, floatx80_infinity.high,
+ floatx80_infinity.low);
+ }
+
+ if (aExp == 0 && aSig == 0) {
+ return packFloatx80(0, one_exp, one_sig);
+ }
+
+ 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;
+
+ fp0 = a;
+
+ compact = floatx80_make_compact(aExp, aSig);
+
+ if (compact < 0x3FB98000 || compact > 0x400B9B07) {
+ /* |X| > 16480 LOG2/LOG10 or |X| < 2^(-70) */
+ if (compact > 0x3FFF8000) { /* |X| > 16480 */
+ status->float_rounding_mode = user_rnd_mode;
+ status->floatx80_rounding_precision = user_rnd_prec;
+
+ if (aSign) {
+ return roundAndPackFloatx80(status->floatx80_rounding_precision,
+ 0, -0x1000, aSig, 0, status);
+ } else {
+ return roundAndPackFloatx80(status->floatx80_rounding_precision,
+ 0, 0x8000, aSig, 0, status);
+ }
+ } else { /* |X| < 2^(-70) */
+ status->float_rounding_mode = user_rnd_mode;
+ status->floatx80_rounding_precision = user_rnd_prec;
+
+ a = floatx80_add(fp0, float32_to_floatx80(
+ make_float32(0x3F800000), status),
+ status); /* 1 + X */
+
+ float_raise(float_flag_inexact, status);
+
+ return a;
+ }
+ } else { /* 2^(-70) <= |X| <= 16480 LOG 2 / LOG 10 */
+ fp1 = fp0; /* X */
+ fp1 = floatx80_mul(fp1, float64_to_floatx80(
+ make_float64(0x406A934F0979A371),
+ status), status); /* X*64*LOG10/LOG2 */
+ n = floatx80_to_int32(fp1, status); /* N=INT(X*64*LOG10/LOG2) */
+ fp1 = int32_to_floatx80(n, status);
+
+ j = n & 0x3F;
+ l = n / 64; /* NOTE: this is really arithmetic right shift by 6 */
+ if (n < 0 && j) {
+ /* arithmetic right shift is division and
+ * round towards minus infinity
+ */
+ l--;
+ }
+ m = l / 2; /* NOTE: this is really arithmetic right shift by 1 */
+ if (l < 0 && (l & 1)) {
+ /* arithmetic right shift is division and
+ * round towards minus infinity
+ */
+ m--;
+ }
+ m1 = l - m;
+ m1 += 0x3FFF; /* ADJFACT IS 2^(M') */
+
+ adjfact = packFloatx80(0, m1, one_sig);
+ fact1 = exp2_tbl[j];
+ fact1.high += m;
+ fact2.high = exp2_tbl2[j] >> 16;
+ fact2.high += m;
+ fact2.low = (uint64_t)(exp2_tbl2[j] & 0xFFFF);
+ fact2.low <<= 48;
+
+ fp2 = fp1; /* N */
+ fp1 = floatx80_mul(fp1, float64_to_floatx80(
+ make_float64(0x3F734413509F8000), status),
+ status); /* N*(LOG2/64LOG10)_LEAD */
+ fp3 = packFloatx80(1, 0x3FCD, LIT64(0xC0219DC1DA994FD2));
+ fp2 = floatx80_mul(fp2, fp3, status); /* N*(LOG2/64LOG10)_TRAIL */
+ fp0 = floatx80_sub(fp0, fp1, status); /* X - N L_LEAD */
+ fp0 = floatx80_sub(fp0, fp2, status); /* X - N L_TRAIL */
+ fp2 = packFloatx80(0, 0x4000, LIT64(0x935D8DDDAAA8AC17)); /* LOG10 */
+ fp0 = floatx80_mul(fp0, fp2, status); /* R */
+
+ /* EXPR */
+ fp1 = floatx80_mul(fp0, fp0, status); /* S = R*R */
+ fp2 = float64_to_floatx80(make_float64(0x3F56C16D6F7BD0B2),
+ status); /* A5 */
+ fp3 = float64_to_floatx80(make_float64(0x3F811112302C712C),
+ status); /* A4 */
+ fp2 = floatx80_mul(fp2, fp1, status); /* S*A5 */
+ fp3 = floatx80_mul(fp3, fp1, status); /* S*A4 */
+ fp2 = floatx80_add(fp2, float64_to_floatx80(
+ make_float64(0x3FA5555555554CC1), status),
+ status); /* A3+S*A5 */
+ fp3 = floatx80_add(fp3, float64_to_floatx80(
+ make_float64(0x3FC5555555554A54), status),
+ status); /* A2+S*A4 */
+ fp2 = floatx80_mul(fp2, fp1, status); /* S*(A3+S*A5) */
+ fp3 = floatx80_mul(fp3, fp1, status); /* S*(A2+S*A4) */
+ fp2 = floatx80_add(fp2, float64_to_floatx80(
+ make_float64(0x3FE0000000000000), status),
+ status); /* A1+S*(A3+S*A5) */
+ fp3 = floatx80_mul(fp3, fp0, status); /* R*S*(A2+S*A4) */
+
+ fp2 = floatx80_mul(fp2, fp1, status); /* S*(A1+S*(A3+S*A5)) */
+ fp0 = floatx80_add(fp0, fp3, status); /* R+R*S*(A2+S*A4) */
+ fp0 = floatx80_add(fp0, fp2, status); /* EXP(R) - 1 */
+
+ fp0 = floatx80_mul(fp0, fact1, status);
+ fp0 = floatx80_add(fp0, fact2, status);
+ fp0 = floatx80_add(fp0, fact1, status);
+
+ status->float_rounding_mode = user_rnd_mode;
+ status->floatx80_rounding_precision = user_rnd_prec;
+
+ a = floatx80_mul(fp0, adjfact, status);
+
+ float_raise(float_flag_inexact, status);
+
+ return a;
+ }
+}