fsgnj.s

Floating-Point Sign-Inject Single-Precision

This instruction is defined by:

Encoding

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Synopsis

The fsgnj.s instruction produces a result that takes all bits except the sign bit from fs1. The result’s sign bit is taken from fs2’s sign bit, and the result is written to the destination register `fd. Sign-injection instructions do not set floating-point exception flags, nor do they canonicalize NaNs.

Access

M HS U VS VU

Always

Always

Always

Always

Always

Decode Variables

Bits<5> fs2 = $encoding[24:20];
Bits<5> fs1 = $encoding[19:15];
Bits<5> fd = $encoding[11:7];

Execution

  • Pruned, XLEN == 64

  • Original

check_f_ok($encoding);
Bits<32> sp_value = {f[fs2][31], f[fs1][30:0]};
if (implemented?(ExtensionName::D)) {
  f[fd] = nan_box<32, 64>(sp_value);
} else {
  f[fd] = sp_value;
}
mark_f_state_dirty();
check_f_ok($encoding);
Bits<32> sp_value = {f[fs2][31], f[fs1][30:0]};
if (implemented?(ExtensionName::D)) {
  f[fd] = nan_box<32, 64>(sp_value);
} else {
  f[fd] = sp_value;
}
mark_f_state_dirty();

Exceptions

This instruction may result in the following synchronous exceptions:

  • IllegalInstruction