For example we have seen that the behavior of oating

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Unformatted text preview: where the latter outcome only occurs when one of the values is a Æ Æ . As an example, consider the following procedure: 1 2 3 4 int less(double x, double y) { return x < y; } The compiled code for the function body is shown below: 1 2 3 4 5 6 fldl 16(%ebp) fcompl 8(%ebp) fnstsw %ax andb $69,%ah sete %al movzbl %al,%eax Push y Compare y:x Store floating point status word in %ax Mask all but bits 0, 2, and 6 Test for comparison outcome of 0 (>) Copy low order byte to result, and set rest to 0 Practice Problem 3.29: Show how by inserting a single line of assembly code into the code sequence shown above you can implement the following function: 1 2 3 4 int greater(double x, double y) { return x > y; } This completes our coverage of assembly-level, floating-point programming with IA32. Even experienced programmers find this code arcane and difficult to read. The stack-based operations, the awkwardness of getting status results from the FPU to the main processor, and the many subtleties of floating-point co...
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This note was uploaded on 09/02/2010 for the course ELECTRICAL 360 taught by Professor Schultz during the Spring '10 term at BYU.

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