Assembly Language Reimagined: Programming the Intel x64 Microprocessor in Linux

© The Author(s), under exclusive license to APress Media, LLC, part of Springer Nature 2025

J. SchwartzmanAssembly Language Reimaginedhttps://doi.org/10.1007/979-8-8688-1724-3_8

8. Using Floating Point Registers

John Schwartzman¹  

(1)

Ellicott City, MD, USA

 

We’re now going to resurrect the cmdline program from Chapter 4. In that program, we passed some string parameters into the program on the command line. This time we’re going to pass in some string parameters, but we’ll treat them as doubles and get their values using the glibc function atof() (atof stands for ASCII to float). We’ll read in some values and treat them as doubles (32-bit values). To do that, we need to use one of the floating point registers, xmm0.

  1 // sum.c - retrieve floats ...