movl

I/R/M, I/R/M

O/S/Z/A/C

This copies a word of data from one location to another. movl %eax, %ebx copies the contents of %eax to %ebx

movb

I/R/M, I/R/M

O/S/Z/A/C

Same as movl, but operates on individual bytes.

leal

M, I/R/M

O/S/Z/A/C

This takes a memory location given in the standard format, and, instead of loading the contents of the memory location, loads the computed address. For example, leal 5 (%ebp, %ecx, 1), %eax loads the address computed by 5 + %ebp + 1*%ecx and stores that in %eax

popl

R/M

O/S/Z/A/C

Pops the top of the stack into the given location. This is equivalent to performing movl (%esp), R/M followed by addl $4, %esp.popfl is a variant which pops the top of the stack into the %eflags register.

pushl

I/R/M

O/S/Z/A/C

Pushes the given value onto the stack. This is the equivalent to performing subl $4, %esp followed by movl I/R/M, (%esp).pushfl is a variant which pushes the current contents of the %eflags register onto the top of the stack.

xchgl

R/M, R/M

O/S/Z/A/C

Exchange the values of the given operands.