What does the syntax constant(register) mean?

Question

I'm learning the AT&T syntax for the Intel x86 architecture, and I'm a bit clueless as to the following syntax's meaning:

1. Shrb $1, 2(%esp)
2. Incw 2(%esp)

My initial interpretation was:

1. esp = (esp + 2) >> 1
2. esp = esp + 2

I can't find any reference for using increase in this way, which leads me to believe I'm more fundamentally flawed here.

Is my interpretation correct, or am I completely off-base? Thank you for your time.

Answer 1

Neither. Just as (%esp) refers to the memory location at %esp (e.g, treating %esp as a pointer), 2(%esp) refers to the memory location at %esp + 2.