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AT & T Floating Point Syntax Arithmetic Link

Last week, I tried to find a decent resource for floating-point arithmetic for x86 assembly using the AT & T syntax. Ideally, a list of opcode what they do and where the floats are stored. I am familiar with the performance of IEEE 754. I am not familiar with the floating point stack and any assembly related to floating point arithmetic.

It’s strange how hard it is to find.

EDIT: I was looking at gcc -S output for the last month while studying assembly. This is how I understood everything except floating point arithmetic. Even after going through dozens of small programs compiled without optimization, I still can’t learn much about floating point and stack codes. I found only trivial examples on the Internet.

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Good. Start over with Intel syntax because most x86 build encoders use it. Intel manuals are a great resource for learning how x86 handles floating point things.

After you learn the x86 assembly in general, the AT & T syntax is not that difficult to learn. Key notes:

  • Registers
  • have the % prefix; numeric constants are prefixed with $
  • register order is replaced for most instructions with two operands (i.e. source first, last object)
  • team names determine the size; so instead of mov dword ptr [ebx], 1337 you can say movl $1337, (%ebx) .
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