SH7670 Datasheet, PDF (102/1292 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7670 Series

Section 3 Floating-Point Unit (FPU)
3.2 Data Formats
3.2.1 Floating-Point Format
A floating-point number consists of the following three fields:
• Sign (s)
• Exponent (e)
• Fraction (f)
This LSI can handle single-precision and double-precision floating-point numbers, using the
formats shown in figures 3.1 and 3.2.
31 30
23 22
0
s
e
f
Figure 3.1 Format of Single-Precision Floating-Point Number
63 62
52 51
0
s
e
f
Figure 3.2 Format of Double-Precision Floating-Point Number
The exponent is expressed in biased form, as follows:
e = E + bias
The range of unbiased exponent E is E_min – 1 to E_max + 1. The two values E_min – 1 and E_max + 1 are
distinguished as follows. E_min – 1 indicates zero (both positive and negative sign) and a
denormalized number, and E_max + 1 indicates positive or negative infinity or a non-number (NaN).
Table 3.1 shows E_min and E_max values.
Rev. 1.00 Nov. 14, 2007 Page 76 of 1262
REJ09B0437-0100