diff --git a/asm.jrt b/asm.jrt
index f52c87d..4bbdee9 100755
--- a/asm.jrt
+++ b/asm.jrt
@@ -6,6 +6,8 @@ var target
 var op-encode
 var lastop
 
+var is-byteptr : byteptr 1 is-byteptr ! ;
+
 var current-oparg
 var opargs-remaining
 array oparg1 3 cells allot
@@ -35,7 +37,8 @@ array oparg2 3 cells allot
 ( ie. inc [bx] vs inc byte [bx]?? )
 ( or do we just say incb? )
 
-: bytearg? ( -- f ) oparg-breg? swap-args oparg-breg? or swap-args ;
+: byteop? ( -- f ) 
+  oparg-breg? swap-args oparg-breg? or swap-args is-byteptr @ or ;
 : byteval? ( v -- f ) 0xff00 & dup 0xff00 = swap 0 = or ;
 
 : operror ( err -- ) lastop @ wordname type s" : " type type cr ;
@@ -79,6 +82,7 @@ array oparg2 3 cells allot
 0x25 reg es 0x27 reg ss 0x2d reg cs 0x2f reg ds
 
 : start-op ( does-ptr argcount -- )
+  0 is-byteptr !
   opargs-remaining @ if s" not enough arguments" operror then
   opargs-remaining ! cell - lastop ! arg1 ;
 : prefix create , does> @ >t ;
@@ -118,16 +122,16 @@ array oparg2 3 cells allot
 ( convention: words ending in * mean "will return if matched" )
 : disp>t oparg-val @ memarg>dispsize 
   dup 1 = if drop >t else 2 = if w>t else drop then then ;
-: imm?>t oparg-imm? if oparg-val @ dup byteval? if >t else w>t then then ;
+: imm?>t oparg-imm? if oparg-val @ byteop? if >t else w>t then then ;
 
 : >wreg+op* ( base -- )
   oparg-wreg? if oparg-val @ | >t rdrop else drop then ;
 : >segreg+op* ( off -- ) 
   oparg-segreg? if oparg-val @ 0x0f & 1 << + >t rdrop else drop then ;
-: >mem* ( reg op -- )
-  oparg-mem? if 
-    >t memarg>mod+rm modrm>t disp>t swap-args imm?>t rdrop 
-  else 2drop then ;
+: >mem ( reg op -- ) >t memarg>mod+rm modrm>t disp>t swap-args imm?>t ;
+: >mem* oparg-mem? byteop? not and if >mem rdrop else 2drop then ;
+: >bmem* oparg-mem? byteop? and if >mem rdrop else 2drop then ;
+
 : >regreg ( reg op -- ) >t regarg>mod+rm modrm>t ;
 : >byte-regreg* ( reg op -- ) oparg-breg? if >regreg rdrop else 2drop then ;
 : >regreg* ( reg op -- ) oparg-wreg? if >regreg rdrop else 2drop then ;
@@ -158,9 +162,47 @@ array oparg2 3 cells allot
   1 0xfe >byte-regreg*
   1 0xff >regreg*
   0 0xff >mem*
+  1 0xfe >bmem*
   invalid-args ;
-1 :op decb
-  1 0xfe >byte-regreg*
-  1 0xfe >mem*
-  invalid-args ;
+1 :op int
+  oparg-imm? if oparg-val @ dup 3 = if drop 0xcc t> else 0xcd t> t> then
+  else invalid-args then ;
 
+: diffaddr ( addr opsize -- diff ) target @ + - ;
+: >short-jmp* ( op -- ) oparg-type @ 3 = if oparg-base @ -1 = if
+    oparg-val @ 2 diffaddr dup byteval? if swap >t >t rdrop return else drop
+  then then then drop ;
+ 
+1 :op jo  0x70 >short-jmp* invalid-args ;
+1 :op jno 0x71 >short-jmp* invalid-args ;
+1 :op jb  0x72 >short-jmp* invalid-args ;
+1 :op jnb 0x73 >short-jmp* invalid-args ;
+1 :op jz  0x74 >short-jmp* invalid-args ;
+1 :op jnz 0x75 >short-jmp* invalid-args ;
+1 :op jbe 0x76 >short-jmp* invalid-args ;
+1 :op ja  0x77 >short-jmp* invalid-args ;
+1 :op js  0x78 >short-jmp* invalid-args ;
+1 :op jns 0x79 >short-jmp* invalid-args ;
+1 :op jpe 0x7a >short-jmp* invalid-args ;
+1 :op jpo 0x7b >short-jmp* invalid-args ;
+1 :op jl  0x7c >short-jmp* invalid-args ;
+1 :op jge 0x7d >short-jmp* invalid-args ;
+1 :op jle 0x7e >short-jmp* invalid-args ;
+1 :op jg  0x7f >short-jmp* invalid-args ;
+1 :op loopnz 0xe0 >short-jmp* invalid-args ;
+1 :op loopz  0xe1 >short-jmp* invalid-args ;
+1 :op loop   0xe2 >short-jmp* invalid-args ;
+1 :op jcxz   0xe3 >short-jmp* invalid-args ;
+
+2 :op xchg
+  arg2 oparg-reg? oparg-val @ 0x00 = arg1 oparg-wreg? and 
+  if 0x90 >wreg+op* then
+  invalid-args ;
+2 :op mov
+  arg2 oparg-imm? arg1 if
+    oparg-wreg? if oparg-val @ 0xb8 | >t arg2 oparg-val @ w>t return then
+    oparg-breg? if oparg-val @ 0x0f & 0xb0 | >t arg2 oparg-val @ >t return then
+    0 0xc6 >bmem*
+    0 0xc7 >mem* 
+  then
+  invalid-args ;