I have confusion regarding Expected flag for FCVT.WU.S Instruction when input is given -ve floating point number.
Section 11.7 of RISC-V Spec Says “FCVT.WU.S, FCVT.LU.S, FCVT.S.WU, and
FCVT.S.LU variants convert to or from unsigned integer values. If the rounded result is not representable in the destination format, it
is clipped to the nearest value and the invalid flag is set. Table 11.4 gives the range of valid inputs
for FCVT.int.S and the behavior for invalid inputs”
All floating-point conversion instructions raise the Inexact exception if the result differs from its
operand value, yet is representable in the destination format.
Section 5.8 of IEEE 754 Spec Says “ When a NaN or infinite operand cannot be represented in the destination format and this cannot otherwise
be indicated, the invalid operation exception shall be signaled. When a numeric operand would convert to
an integer outside the range of the destination format, the invalid operation exception shall be signaled if
this situation cannot otherwise be indicated.
When the value of the conversion operation’s result differs from its operand value, yet is representable in
the destination format, some conversion operations are specified below to signal the inexact exception and
others to not signal the inexact exception.”
X27 =86400700(-3.611632924504552e-35 D)
As per table, fcvt.wu.s minimum input valid =0 and 86400700 is not valid input. So o/p is is 0. But for FCSR flag, what should be result flag.
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As per table, fcvt.wu.s minimum input valid =0 and 86400700 is not valid input.
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