bug fix of bitnplusone calculation in divround of posit<16,2>

stillwater-sc · Jan 2, 2024 · 7e149f7 · 7e149f7
1 parent 40a475a
commit 7e149f7
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Showing 2 changed files with 10 additions and 5 deletions.
diff --git a/include/universal/number/posit/specialized/posit_16_2.hpp b/include/universal/number/posit/specialized/posit_16_2.hpp
@@ -863,9 +863,7 @@ class posit<NBITS_IS_16, ES_IS_2> {
 			uint16_t final_fbits = uint16_t(fraction >> (reglen + 2));
 			bool bitNPlusOne = false;
 			if (reglen != 14) {
-				//std::cout << "fraction  : " << to_binary(fraction, 16, true) << '\n';
-				//std::cout << "nplusone  : " << to_binary((fraction >> (reglen - 1)), 16, true) << '\n';
-				bitNPlusOne = bool((fraction >> (reglen - 1)) & 0x1);
+				bitNPlusOne = bool((fraction >> (reglen + 1)) & 0x1);
 			}
 			else if (final_fbits > 0) {
 				final_fbits = 0;

diff --git a/static/posit/specialized/posit_16_2.cpp b/static/posit/specialized/posit_16_2.cpp
@@ -84,12 +84,19 @@ try {
 
 #if MANUAL_TESTING
 
+	TestWithValues(-9.0390625, -0.0225372314453125);
+	TestWithValues(1.1368683772161602974e-13, 8.5265128291212022305e-14);
+	/*
+		-0.3614501953125          /= -281474976710656          != 2.2204460492503130808e-16 golden reference is 8.8817841970012523234e-16
+		0b1.01.10.01110010001     /= 0b1.11111111111110.0.     != 0b0.00000000000001.0.     golden reference is 0b0.00000000000001.1.
+	*/
+	TestWithValues(-0.3614501953125, -281474976710656);
+
 	nrOfFailedTestCases += ReportTestResult(VerifyBinaryOperatorThroughRandoms<nbits, es>(reportTestCases, OPCODE_IPA, 100), tag, "+=             (native)  ");
 	nrOfFailedTestCases += ReportTestResult(VerifyBinaryOperatorThroughRandoms<nbits, es>(reportTestCases, OPCODE_IPS, 100), tag, "-=             (native)  ");
 	nrOfFailedTestCases += ReportTestResult(VerifyBinaryOperatorThroughRandoms<nbits, es>(reportTestCases, OPCODE_IPM, 100), tag, "*=             (native)  ");
-	nrOfFailedTestCases += ReportTestResult(VerifyBinaryOperatorThroughRandoms<nbits, es>(true, OPCODE_IPD, 100), tag, "/=             (native)  ");
+	nrOfFailedTestCases += ReportTestResult(VerifyBinaryOperatorThroughRandoms<nbits, es>(reportTestCases, OPCODE_IPD, 100), tag, "/=             (native)  ");
 
-	TestWithValues(1.1368683772161602974e-13, 8.5265128291212022305e-14);
 	goto epilog;
 
 	std::cout << "Exhaustive tests" << std::endl;