Texas Instruments TMS320C3x User Manual
Page 126
Floating-Point Conversion (IEEE Std. 754)
5-21
Data Formats and Floating-Point Operation
5.4.2
Converting 2s-Complement TMS320C3x Floating-Point Format to IEEE Format
This conversion is performed according to the following table:
Table 5–2. Converting 2s-Complement Floating-Point Format to IEEE Format
If these values are present
Then these values equal
Case
e
2
s
2
f
2
e
IEEE
s
IEEE
f
IEEE
1
–128
00h
0
00 0000h
2
–127
00h
0
00 0000h
3
–126
≤
e
2
≤
127
0
e
2
+7Fh
0
f
2
4
–126
≤
e
2
≤
127
1
≠
0
e
2
+7Fh
0
f
2
+1
†
5
–126
≤
e
2
≤
127
1
0
e
2
+80h
1
00 0000h
6
127
1
0
FFh
1
00 0000h
†
f
2
= 2s-complement of f
2 .
Case 1 maps a 2s-complement 0 to a positive IEEE 0.
Case 2 maps the 2s-complement numbers that are too small to be repre-
sented as normalized IEEE numbers to a positive IEEE 0.
Case 3 maps the positive 2s-complement numbers that are not covered by
case 2 into the identically valued IEEE number.
Case 4 maps the negative 2s-complement numbers with a nonzero fraction
that are not covered in case 2 into the identically valued IEEE number.
Case 5 maps all the negative 2s-complement numbers with a 0 fraction, except
for the most negative 2s-complement number and those that are not covered
in case 2, into the identically valued IEEE number.
Case 6 maps the most negative 2s-complement number to the IEEE negative
infinity.