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Section 6 Floating-Point Unit
SH7751 Group, SH7751R Group
Page 186 of 1128
R01UH0457EJ0301 Rev. 3.01
Sep 24, 2013
b. FPU
Operation result: H'00800000
FPSCR: H'00041004
•
Double-precision
When FPSCR.RM = 00 (Round to Nearest) and FPSCR.PR = 1 (double-precision), and the
FDIV instruction (H'001FFFFF FFFFFFFF / H'40000000 00000000) is executed.
a. According to IEEE754 standard
Operation result: H'00100000 00000000
FPSCR: H'000C300C
b. FPU
Operation result: H'00100000 00000000
FPSCR: H'000C1004
Workarounds
1. Use FPSCR.RM = 01, that is to say Round to Zero rather than Round to Nearest mode.
2. Use FPSCR.RM = 00, that is to say Round to Nearest mode, and set the enable field to 1 to
enable generation of inexact exceptions so that the exception handling routine can be used to
check whether or not an underflow has occurred.
6.7.2
Setting of Overflow Flag by FIPR or FTRV Instruction
When the maximum error produced by the FIPR or FTRV instruction exceeds the maximum value
expressible as a normalized number (H'7F7FFFFF), the overflow flag may be set, even through
the operation result is a positive or negative zero (H'00000000 or H'80000000).
Example:
The operation result (FR7) after executing the instruction FIPR FV4, FV0 is
H'00000000 (positive zero), but the overflow flag may be set nevertheless.
FPSCR = H'00040001
FR0 = H'FF7EF631 , FR1 = H80000000 , FR2 = H'8087F451 , FR3 = H'7F7EF631
FR4 = H'7F7EF631 , FR5 = H'0087F451 , FR6 = H'7F7EF631 , FR7 = H'7F7EF631
Workaround:
Avoid using the FIPR and FTRV instructions, and use the FADD, FMUL, and
FMAC instructions instead.
Содержание SH7751 Group
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Страница 320: ...Section 9 Power Down Modes SH7751 Group SH7751R Group Page 266 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 344: ...Section 10 Clock Oscillation Circuits SH7751 Group SH7751R Group Page 290 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 388: ...Section 12 Timer Unit TMU SH7751 Group SH7751R Group Page 334 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 800: ...Section 17 Smart Card Interface SH7751 Group SH7751R Group Page 746 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 848: ...Section 19 Interrupt Controller INTC SH7751 Group SH7751R Group Page 794 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 876: ...Section 20 User Break Controller UBC SH7751 Group SH7751R Group Page 822 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 1036: ...Section 22 PCI Controller PCIC SH7751 Group SH7751R Group Page 982 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 1152: ...Appendix C Mode Pin Settings SH7751 Group SH7751R Group Page 1098 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
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Страница 1186: ... SH7751 Group SH7751R Group User s Manual Hardware R01UH0457EJ0301 Previous Number REJ09B0370 0400 ...