Add inline comments with reference to literature

timleslie · timleslie · commit 6829744a2319 · 2020-10-18T15:51:43.000+11:00
diff --git a/BLAS/SRC/drotmg.f b/BLAS/SRC/drotmg.f
@@ -153,6 +153,9 @@ SUBROUTINE DROTMG(DD1,DD2,DX1,DY1,DPARAM)
              DD2 = DD2/DU
              DX1 = DX1*DU
            ELSE
+*            This code path if here for safety. We do not expect this
+*            condition to ever hold except in edge cases with rounding
+*            errors. See DOI: 10.1145/355841.355847
              DFLAG = -ONE
              DH11 = ZERO
              DH12 = ZERO
diff --git a/BLAS/SRC/srotmg.f b/BLAS/SRC/srotmg.f
@@ -153,6 +153,9 @@ SUBROUTINE SROTMG(SD1,SD2,SX1,SY1,SPARAM)
              SD2 = SD2/SU
              SX1 = SX1*SU
            ELSE
+*            This code path if here for safety. We do not expect this
+*            condition to ever hold except in edge cases with rounding
+*            errors. See DOI: 10.1145/355841.355847
              SFLAG = -ONE
              SH11 = ZERO
              SH12 = ZERO
