Based on your answers to 3.13.4 and 3.13.5, does (A × B) × C = A × (B × C)?

Problem  3.13.4

Calculate (A × B) × C by hand, assuming A, B, and C are stored in the modified 16-bit NVIDIA format described in 3.11.2 (and also described in the text). Assume 1 guard, 1 round bit, and 1 sticky bit, and round to the nearest even. Show all the steps, and write your answer in both the 16-bit floating point format and in decimal.

Problem  3.13.5

Calculate A × (B × C) by hand, assuming A, B, and C are stored in the modified 16-bit NVIDIA format described in 3.11.2 (and also described in the text). Assume 1 guard, 1 round bit, and 1 sticky bit, and round to the nearest even. Show all the steps, and write your answer in both the 16-bit floating point format and in decimal.

Problem 3.11.2

NVIDIA has a “half” format, which is similar to IEEE 754 except that it is only 16 bits wide. The leftmost bit is still the sign bit, the exponent is 5 bits wide and stored in excess-56 format, and the mantissa is 10 bits long. A hidden 1 is assumed. Write down the bit pattern assuming a modified version of this format, which uses an excess-16 format to store the exponent. Comment on how the range and accuracy of this 16-bit floating point format compares to the single precision IEEE 754 standard.

The following table shows further sets of decimal numbers.

Transcribed Image Text:

a. b. A 3.41796875 10-3 1.140625 x 10² В 6.34765625 x 10-³ -9.135 x 10² C 1.05625 x 10² 9.84375 x 10-¹