Class: Ragweed::Rasm::Cmp

Inherits:
Instruction show all
Defined in:
lib/ragweed/rasm/isa.rb

Overview

CMP is SUB + condition code

Instance Attribute Summary

Attributes inherited from Instruction

#dst, #src

Instance Method Summary collapse

Methods inherited from Instruction

#add, #coerce, #dst_imm?, #dst_lab?, #dst_reg?, i, #locate, #modrm, #patch, #sib, #src_imm?, #src_lab?, #src_reg?

Constructor Details

#initialize(dst = nil, src = nil) ⇒ Cmp

3c imm8 3d imm 80/7 r/m8, imm8 81/7 r/m, imm 83/7 r/m, imm8 38 r/m8, r8 39 r/m, r 3a r8, r/m8 3b r, r/m



717
 
# File 'lib/ragweed/rasm/isa.rb', line 717

def initialize( dst=nil, src=nil); super dst, src; end

Instance Method Details

#to_s ⇒ Object 



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# File 'lib/ragweed/rasm/isa.rb', line 719

def to_s
  if not @dst
    raise(BadArg, "need immed for implicit ax") if not src_imm?
    if @src.val < 0x100
      add(0x3c)
      add(@src.val)
    else
      add(0x3d)
      add(@src.val)
    end
  else
    raise(BadArg, "need reg dst") if not dst_reg?
    if src_imm?
      raise NotImp if @dst.byte
      if @src.val < 0x100
        add(0x83)
        add(modrm(@dst, Edi.clone))
        add(@src.val)
      else
        add(0x81)
        add(modrm(@dst, Edi.clone))
        add(@src.val)
      end
    else
      if @dst.indir
        add(0x39)
        add(modrm(@src, @dst))
        add(@dst.disp)
      else
        add(0x3b)
        add(modrm(@src, @dst))
        add(@dst.disp)
      end
    end
  end
  super
end