diff --git a/a.c b/a.c
index a49029f..ac23ecd 100644
--- a/a.c
+++ b/a.c
@@ -2,8 +2,10 @@
 #undef malloc
 #undef realloc
 #undef free
+#undef fopen
 NR V die(IM C*f,...)VA(f,vfprintf(stderr,f,ap),fputc('\n',stderr),exit(1))
 V asrt(B b,IM C*m){N(b,die(m))}
 V*mk(W sz){V*p;N(p=calloc(1,sz),die("oom"))R p;}
 V*remk(V*p,W sz){N(p=realloc(p,sz),die("oom"))R p;}
 V del(V*p){free(p);}
+F xopen(IM C*n,IM C*p){F f;N(f=fopen(n,p),die("unable to open file `%s`",n))R f;}
diff --git a/a.h b/a.h
index c6d28a0..6d3bf05 100644
--- a/a.h
+++ b/a.h
@@ -1,7 +1,9 @@
+#include<libgen.h>
 #include<stdint.h>
 #include<stdio.h>
 #include<stdlib.h>
 #include<string.h>
+#include<unistd.h>
 #define IM const
 #define N(a,...)Q(!(a),__VA_ARGS__)
 #define NR _Noreturn
@@ -11,6 +13,7 @@
 #define SZ sizeof
 #define VA(a,...){va_list ap;va_start(ap,a);__VA_ARGS__;va_end(ap);}
 #define WH(a,...)while((a)){__VA_ARGS__;}
+#define WIF(f,n,p,...){f=xopen(n,p);__VA_ARGS__;fclose(f);}
 #define _ static
 typedef void V;
 typedef int I;
@@ -18,12 +21,15 @@ typedef char C;
 typedef uint8_t B;
 typedef uint16_t H;
 typedef uint32_t W;
+typedef FILE*F;
 
 NR V die(IM C*,...);
 V asrt(B,IM C*);
 V*mk(W);
 V*remk(V*,W);
 V del(V*);
+F xopen(IM C*,IM C*);
 #define malloc B use_mk_instead[-1]
 #define realloc B use_remk_instead[-1]
 #define free B use_del_instead[-1]
+#define fopen B use_xopen_instead[-1]
diff --git a/as.c b/as.c
index c8fc23c..1de4957 100644
--- a/as.c
+++ b/as.c
@@ -33,9 +33,11 @@ Ht labels;
 Ht macros;
 Vec refs;
 
-_ V builtin(S*t){S x=*t;++x.p,--x.l;
-  Q(seql(Sl("org"),x),tasrt(next(t),'#'),mel=tton(*t))OR
-  Q(seql(Sl("res"),x),tasrt(next(t),'#'),mel+=tton(*t))OR
+#define BE(y,...)Q(seql(Sl(y),x),__VA_ARGS__)OR
+_ V builtin(S*t){FILE*f;S y,x=*t;++x.p,--x.l;
+  BE("org",tasrt(next(t),'#'),mel=tton(*t))
+  BE("res",tasrt(next(t),'#'),mel+=tton(*t))
+  BE("emb",tasrt(y=next(t),'"'),y.p[y.l-1]=0;WIF(f,(C*)y.p+1,"rb",mel+=fread(meb+mel,1,(W)0-1,f)))
   tw(x),die(" unknown builtin");}
 
 _ V pass1(S*t){S x=*t;B c,o;c=*x.p;
@@ -61,10 +63,7 @@ _ V run(V){S t={0,inb};
 I main(I ac,C**av){FILE *f;
   Q(3!=ac,die("usage: as INPUT.ASM OUTPUT.ROM"))
   /*todo:this is undefined behaviour for binary streams (SEEK_END)*/
-  N(f=fopen(av[1],"rb"),die("couldn't open input file"))
-  fseek(f,0,SEEK_END),inl=ftell(f),fseek(f,0,SEEK_SET),inb=mk(inl+1),fread(inb,1,inl,f),fclose(f),inb[inl]=0;
-  run(),del(inb);
-  N(f=fopen(av[2],"wb"),die("couldn't open output file"))
-  fwrite(meb+0x100,1,mel-0x100,f);
+  WIF(f,av[1],"rb",fseek(f,0,SEEK_END),inl=ftell(f),fseek(f,0,SEEK_SET),inb=mk(inl+1),fread(inb,1,inl,f))
+  WIF(f,av[2],"wb",Q(chdir(dirname(av[1])),die("?"))inb[inl]=0,run(),del(inb),fwrite(meb+0x100,1,mel-0x100,f))
   printf("done: %d bytes wrote\n",mel-0x100);
   R 0;}
diff --git a/kip-io-disk.c b/kip-io-disk.c
new file mode 100644
index 0000000..2c4769f
--- /dev/null
+++ b/kip-io-disk.c
@@ -0,0 +1,12 @@
+#include<stdio.h>
+#include"kip.h"
+#define BLK 0x1000
+_ FILE*f;
+_ W z,s,a;
+
+V disk_open(IM C*n){f=xopen(n,"r+b"),fseek(f,0,SEEK_END),z=ftell(f),fseek(f,0,SEEK_SET);}
+V disk_close(V){Q(f,fclose(f));}
+
+DEV(disk_size,((V)x),(R z))
+DEV(disk_seek,(fseek(f,BLK*(s=x),SEEK_SET)),(R s))
+DEV(disk_read,(a=fread(mem+x,1,BLK,f)),(R a))
diff --git a/kip.c b/kip.c
index be3de61..ac04930 100644
--- a/kip.c
+++ b/kip.c
@@ -12,8 +12,8 @@ I main(I ac,IM C*av[]){B*b;W l;FILE*f;
 #include"kip-io.def"
   };
 #undef X
-  f=fopen(av[1],"rb"),fseek(f,0,SEEK_END),l=ftell(f),fseek(f,0,SEEK_SET),
-  b=mk(l+1),fread(b,1,l,f),fclose(f),b[l]=0,lod(b,l),front_init();
+  WIF(f,av[1],"rb",fseek(f,0,SEEK_END),l=ftell(f),fseek(f,0,SEEK_SET),b=mk(l+1),fread(b,1,l,f))
+  b[l]=0,lod(b,l),front_init();
   WH(1,front_events(),emu(STEP),front_redraw())
   kip_deinit();}