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M32R-FPU Software Manual (Rev.1.01)
INSTRUCTIONS
3.2 Instruction description
[Supplemental Operation Description]
The results of the FTOS instruction executed based on the Rsrc value, both when DN = 0 and DN = 1,
are shown in below.
DN = 0
Rsrc Value (exponent with no bias)
Rdest
Exception
Rsrc 
≥ 0
+Infinity
When EIT occurs: no change
Invalid Operation Exception
127 
 exp 
 15
Other EIT: H'0000 7FFFF
14 
 exp 
 -126
H'0000 0000 to H'0000 7FFF
No change (Note 1)
+Denormalized value
No change
Unimplemented Exception
+0
H'0000 0000
No change
Rsrc < 0
-0
-Denormalized value
No change
Unimplemented Exception
14 
 exp 
 -126
H'0000 0000 to H'FFFF 8001
No change (Note 1)
127 
 exp 
 15
When EIT occurs: no change
Invalid Operation Exception
-Infinity
Other EIT: H’FFFF 8000
(Note 2)
NaN
QNaN
When EIT occurs: no change
Invalid Operation Exception
Other EIT:
SNaN
Signed bit = 0:H’0000 7FFF
Signed bit = 1:H’FFFF 8000
Note 1: Inexact Exception occurs when rounding is performed.
2: Inexact Exception does not occur when Rsrc = H’CF00 0000.
DN = 1
Rsrc Value (exponent with no bias)
Rdest
Exception
Rsrc 
≥ 0
+Infinity
When EIT occurs: no change
Invalid Operation Exception
127 
 exp 
 15
Other EIT: H'0000 7FFF
14 
 exp 
 -126
H'0000 0000 to H'0000 7FFF
No change (Note 1)
+0, +Denormalized value
H'0000 0000
No change
Rsrc < 0
-0, -Denormalized value
14 
 exp 
 -126
H'0000 0000 to H'FFFF 8001
No change (Note 1)
127 
 exp 
 15
When EIT occurs: no change
Invalid Operation Exception
-Infinity
Other EIT: H'FFFF 8000
(Note 2)
NaN
QNaN
When EIT occurs: no change
Invalid Operation Exception
Other EIT:
SNaN
Signed bit = 0:H’0000 7FFF
Signed bit = 1:H’FFFF 8000
Note 1: Inexact Exception occurs when rounding is performed.
2: No Exceptions occur when Rsrc = H’C700 0000. When Rsrc = H’C700 0001 to H’C700 00FF,
the Inexact Exception occurs and the Invalid Operation Exception does not occur.
FTOS
FTOS
floating point Instructions
Float to short
[M32R-FPU Extended Instruction]