SH7730 Datasheet, PDF (179/1188 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7780 Series

Section 6 Floating-Point Unit (FPU)
Table 6.1 Floating-Point Number Formats and Parameters
Parameter
Total bit width
Sign bit
Exponent field
Fraction field
Precision
Bias
E
max
E
min
Single-Precision
32 bits
1 bit
8 bits
23 bits
24 bits
+127
+127
–126
Double-Precision
64 bits
1 bit
11 bits
52 bits
53 bits
+1023
+1023
–1022
Floating-point number value v is determined as follows:
If E = E_max + 1 and f ≠ 0, v is a non-number (NaN) irrespective of sign s
If E = E_max + 1 and f = 0, v = (–1)^s (infinity) [positive or negative infinity]
If E_min ≤ E ≤ E_max , v = (–1)^s2^E (1.f) [normalized number]
If E = E_min – 1 and f ≠ 0, v = (–1)^s2^Emin (0.f) [denormalized number]
If E = E_min – 1 and f = 0, v = (–1)^s0 [positive or negative zero]
Table 6.2 shows the ranges of the various numbers in hexadecimal notation. For the signaling non-
number and quiet non-number, see section 6.2.2, Non-Numbers (NaN). For the denormalized
number, see section 6.2.3, Denormalized Numbers.
Rev. 1.00 Sep. 19, 2007 Page 131 of 1136
REJ09B0359-0100