diff --git a/include/fh_config.h b/include/fh_config.h
index c24b488..723ffd3 100644
--- a/include/fh_config.h
+++ b/include/fh_config.h
@@ -12,9 +12,11 @@
 #define RETURN_STACK_DEPTH 1024
 #define MAX_NAME_LEN 32
 #define DICT_SIZE 1024
-#define COMPILED_BUFFER_SIZE (1024*1024)
 #define HEAP_SIZE (1024*1024)
 #define MAXLINE 65535
+#define PAD_SIZE 256
+#define WORDBUF_SIZE 128
+#define INPUT_BUFFER_SIZE 256
 
 #define CELL 4
 
diff --git a/include/fh_mem.h b/include/fh_mem.h
index 26a1938..2b25f18 100644
--- a/include/fh_mem.h
+++ b/include/fh_mem.h
@@ -24,14 +24,18 @@ enum fh_error fh_heap_reserve(
 );
 void fh_heap_write(struct fh_thread_s *fh, uint32_t addr, const void *src, uint32_t len);
 enum fh_error fh_heap_put(struct fh_thread_s *fh, const void *src, uint32_t len);
-void fh_heap_copy_from_compile(struct fh_thread_s *fh, uint32_t addr, uint32_t srcaddr, uint32_t len);
+void fh_heap_copy(struct fh_thread_s *fh, uint32_t addr, uint32_t srcaddr, uint32_t len);
 
-enum fh_error fh_compile_reserve(
-    struct fh_thread_s *fh,
-    size_t len,
-    uint32_t *addr
-);
-void fh_compile_write(struct fh_thread_s *fh, uint32_t addr, const void *src, uint32_t len);
-enum fh_error fh_compile_put(struct fh_thread_s *fh, const void *src, uint32_t len);
+static inline char *fh_str_at(struct fh_thread_s *fh, uint32_t addr) {
+  return (char *) &fh->heap[addr];
+}
+
+static inline struct fh_instruction_s *fh_instr_at(struct fh_thread_s *fh, uint32_t addr) {
+  return (void *) &fh->heap[addr];
+}
+
+static inline struct fh_word_s *fh_word_at(struct fh_thread_s *fh, uint32_t addr) {
+  return (struct fh_word_s *) &fh->heap[addr];
+}
 
 #endif //FORTH_FH_MEM_H
diff --git a/include/fh_runtime.h b/include/fh_runtime.h
index 6144cf7..2210d70 100644
--- a/include/fh_runtime.h
+++ b/include/fh_runtime.h
@@ -108,8 +108,7 @@ struct fh_word_s {
   word_exec_t handler;
   /** Indicates that this is a built-in instruction and not a word call */
   bool builtin;
-  /** Indicates that this instruction should always be treated as interpreted,
-   * in practice this is only used for `;` */
+  /** Indicates that this instruction should always be treated as interpreted */
   bool immediate;
   /** Start address in case of user words, or param for builtins */
   union {
@@ -140,13 +139,10 @@ struct fh_thread_s {
   size_t return_stack_top;
   size_t return_stack_hwm;
 
-  /** Data heap */
+  /** Data buffer used for everything */
   uint8_t heap[HEAP_SIZE];
-  size_t heap_top; // aka "HERE"
+  size_t here;
 
-  /** Compile buffer, used for both word data and literals */
-  uint8_t compile[COMPILED_BUFFER_SIZE];
-  size_t compile_top;
   /** Pointer into the compile buffer for execution */
   uint32_t execptr;
 
@@ -154,6 +150,15 @@ struct fh_thread_s {
   struct fh_word_s dict[DICT_SIZE];
   uint32_t dict_top;
 
+  /** Pad buffer */
+  uint8_t pad[PAD_SIZE];
+  /** WORD and pictured output buffer */
+  uint8_t wordbuf[WORDBUF_SIZE];
+
+  /** Input buffer */
+  uint8_t inbuf[INPUT_BUFFER_SIZE];
+  uint32_t inbuf_ptr;
+
   /** Forth state */
   enum fh_state state;
 
diff --git a/src/fh_builtins.c b/src/fh_builtins.c
index 8cd80b7..147a648 100644
--- a/src/fh_builtins.c
+++ b/src/fh_builtins.c
@@ -368,7 +368,7 @@ static enum fh_error w_colon(struct fh_thread_s *fh, const struct fh_word_s *w)
   }
   struct fh_word_s *new_word = &fh->dict[fh->dict_top];
   new_word->index = fh->dict_top;
-  new_word->start = fh->compile_top;
+  new_word->start = fh->here;
   new_word->handler = w_user_word;
 
   return FH_OK;
@@ -409,7 +409,7 @@ static enum fh_error w_literal(struct fh_thread_s *fh, const struct fh_word_s *w
   uint32_t val;
   TRY(ds_pop(fh, &val));
   instr_init(&instr, FH_INSTR_NUMBER, val);
-  TRY(fh_compile_put(fh, &instr, INSTR_SIZE));
+  TRY(fh_heap_put(fh, &instr, INSTR_SIZE));
 
   return FH_OK;
 }
@@ -423,7 +423,7 @@ static enum fh_error w_semicolon(struct fh_thread_s *fh, const struct fh_word_s
   ENSURE_STATE(FH_STATE_COMPILE);
 
   instr_init(&instr, FH_INSTR_ENDWORD, 0);
-  TRY(fh_compile_put(fh, &instr, INSTR_SIZE));
+  TRY(fh_heap_put(fh, &instr, INSTR_SIZE));
 
   /* Return to interpret state */
   fh_setstate(fh, FH_STATE_INTERPRET, 0);
@@ -472,7 +472,7 @@ static enum fh_error w_recurse(struct fh_thread_s *fh, const struct fh_word_s *w
   ENSURE_STATE(FH_STATE_COMPILE);
 
   instr_init(&instr, FH_INSTR_WORD, fh->dict_top);
-  TRY(fh_compile_put(fh, &instr, INSTR_SIZE));
+  TRY(fh_heap_put(fh, &instr, INSTR_SIZE));
 
   return FH_OK;
 }
@@ -724,7 +724,7 @@ static enum fh_error w_type(struct fh_thread_s *fh, const struct fh_word_s *w)
   TRY(ds_pop(fh, &count));
   TRY(ds_pop(fh, &addr));
 
-  FHPRINT("%.*s", count, &fh->heap[addr]);
+  FHPRINT("%.*s", count, fh_str_at(fh, addr));
   return FH_OK;
 }
 
@@ -850,9 +850,9 @@ static enum fh_error w_if(struct fh_thread_s *fh, const struct fh_word_s *w)
 
   ENSURE_STATE(FH_STATE_COMPILE);
 
-  TRY(cs_push(fh, fh->compile_top));
+  TRY(cs_push(fh, fh->here));
   instr_init(&instr, FH_INSTR_JUMPZERO, MAGICADDR_UNRESOLVED);
-  TRY(fh_compile_put(fh, &instr, INSTR_SIZE));
+  TRY(fh_heap_put(fh, &instr, INSTR_SIZE));
   return FH_OK;
 }
 
@@ -866,17 +866,17 @@ static enum fh_error w_else(struct fh_thread_s *fh, const struct fh_word_s *w)
 
   uint32_t ifaddr = 0;
   TRY(cs_pop(fh, &ifaddr));
-  struct fh_instruction_s *if_instr = (void *) &fh->compile[ifaddr];
+  struct fh_instruction_s *if_instr = fh_instr_at(fh, ifaddr);
   if (if_instr->data != MAGICADDR_UNRESOLVED) {
     LOGE("IF-ELSE control stack corruption");
     return FH_ERR_INTERNAL;
   }
 
-  if_instr->data = fh->compile_top + INSTR_SIZE;
+  if_instr->data = fh->here + INSTR_SIZE;
 
-  TRY(cs_push(fh, fh->compile_top));
+  TRY(cs_push(fh, fh->here));
   instr_init(&instr, FH_INSTR_JUMP, MAGICADDR_UNRESOLVED);
-  TRY(fh_compile_put(fh, &instr, INSTR_SIZE));
+  TRY(fh_heap_put(fh, &instr, INSTR_SIZE));
   return FH_OK;
 }
 
@@ -889,13 +889,13 @@ static enum fh_error w_then(struct fh_thread_s *fh, const struct fh_word_s *w)
 
   uint32_t ifaddr = 0;
   TRY(cs_pop(fh, &ifaddr));
-  struct fh_instruction_s *if_instr = (void *) &fh->compile[ifaddr];
+  struct fh_instruction_s *if_instr = fh_instr_at(fh, ifaddr);
   if (if_instr->data != MAGICADDR_UNRESOLVED) {
     LOGE("IF-ELSE control stack corruption");
     return FH_ERR_INTERNAL;
   }
 
-  if_instr->data = fh->compile_top;
+  if_instr->data = fh->here;
   return FH_OK;
 }
 
@@ -911,7 +911,7 @@ static enum fh_error w_until(struct fh_thread_s *fh, const struct fh_word_s *w)
   TRY(cs_pop(fh, &destaddr));
 
   instr_init(&instr, FH_INSTR_JUMPZERO, destaddr);
-  TRY(fh_compile_put(fh, &instr, INSTR_SIZE));
+  TRY(fh_heap_put(fh, &instr, INSTR_SIZE));
   return FH_OK;
 }
 
@@ -920,7 +920,7 @@ static enum fh_error w_begin(struct fh_thread_s *fh, const struct fh_word_s *w)
   (void) w;
   enum fh_error rv;
   ENSURE_STATE(FH_STATE_COMPILE);
-  TRY(cs_push(fh, fh->compile_top)); /* dest */
+  TRY(cs_push(fh, fh->here)); /* dest */
   return FH_OK;
 }
 
@@ -935,11 +935,11 @@ static enum fh_error w_while(struct fh_thread_s *fh, const struct fh_word_s *w)
   uint32_t destaddr = 0;
   TRY(cs_pop(fh, &destaddr));
 
-  TRY(cs_push(fh, fh->compile_top)); // orig
+  TRY(cs_push(fh, fh->here)); // orig
   TRY(cs_push(fh, destaddr)); // dest
 
   instr_init(&instr, FH_INSTR_JUMPZERO, MAGICADDR_UNRESOLVED);
-  TRY(fh_compile_put(fh, &instr, INSTR_SIZE));
+  TRY(fh_heap_put(fh, &instr, INSTR_SIZE));
   return FH_OK;
 }
 
@@ -956,15 +956,15 @@ static enum fh_error w_repeat(struct fh_thread_s *fh, const struct fh_word_s *w)
   TRY(cs_pop(fh, &destaddr));
   TRY(cs_pop(fh, &origaddr));
 
-  struct fh_instruction_s *branch_instr = (void *) &fh->compile[origaddr];
+  struct fh_instruction_s *branch_instr = fh_instr_at(fh, origaddr);
   if (branch_instr->data != MAGICADDR_UNRESOLVED) {
     LOGE("REPEAT control stack corruption");
     return FH_ERR_INTERNAL;
   }
-  branch_instr->data = fh->compile_top + INSTR_SIZE;
+  branch_instr->data = fh->here + INSTR_SIZE;
 
   instr_init(&instr, FH_INSTR_JUMP, destaddr);
-  TRY(fh_compile_put(fh, &instr, INSTR_SIZE));
+  TRY(fh_heap_put(fh, &instr, INSTR_SIZE));
 
   return FH_OK;
 }
@@ -981,7 +981,7 @@ static enum fh_error w_again(struct fh_thread_s *fh, const struct fh_word_s *w)
   TRY(cs_pop(fh, &destaddr));
 
   instr_init(&instr, FH_INSTR_JUMP, destaddr);
-  TRY(fh_compile_put(fh, &instr, INSTR_SIZE));
+  TRY(fh_heap_put(fh, &instr, INSTR_SIZE));
 
   return FH_OK;
 }
@@ -1031,7 +1031,7 @@ static enum fh_error w_unused(struct fh_thread_s *fh, const struct fh_word_s *w)
 {
   (void) w;
   enum fh_error rv;
-  TRY(ds_push(fh, HEAP_SIZE - fh->heap_top));
+  TRY(ds_push(fh, HEAP_SIZE - fh->here));
   return FH_OK;
 }
 
@@ -1126,7 +1126,7 @@ static enum fh_error w_comma(struct fh_thread_s *fh, const struct fh_word_s *w)
   (void) w;
   enum fh_error rv;
 
-  if (fh->heap_top & 3) {
+  if (fh->here & 3) {
     LOGE("HERE not aligned before 'comma'");
     return FH_ERR_ILLEGAL_STORE;
   }
@@ -1141,7 +1141,7 @@ static enum fh_error w_align(struct fh_thread_s *fh, const struct fh_word_s *w)
 {
   (void) w;
   enum fh_error rv;
-  fh->heap_top = WORDALIGNED(fh->heap_top);
+  fh->here = WORDALIGNED(fh->here);
   return FH_OK;
 }
 
diff --git a/src/fh_mem.c b/src/fh_mem.c
index a0ebeae..02a1476 100644
--- a/src/fh_mem.c
+++ b/src/fh_mem.c
@@ -18,7 +18,7 @@ enum fh_error fh_fetch(struct fh_thread_s *fh, uint32_t addr, uint32_t *dst)
       break;
 
     case MAGICADDR_HERE:
-      *dst = fh->heap_top;
+      *dst = fh->here;
       break;
 
     default:
@@ -95,7 +95,7 @@ enum fh_error fh_heap_reserve(
     uint32_t *addr
 )
 {
-  uint32_t p = fh->heap_top;
+  uint32_t p = fh->here;
 
   if (p + len > HEAP_SIZE) {
     return FH_ERR_HEAP_FULL;
@@ -105,7 +105,7 @@ enum fh_error fh_heap_reserve(
     *addr = p;
   }
 
-  fh->heap_top = WORDALIGNED(p + len);
+  fh->here = WORDALIGNED(p + len);
 
   return FH_OK;
 }
@@ -127,45 +127,7 @@ enum fh_error fh_heap_put(struct fh_thread_s *fh, const void *src, uint32_t len)
 }
 
 /** Copy bytes from compile area to heap. The region must have been previously allocated! */
-void fh_heap_copy_from_compile(struct fh_thread_s *fh, uint32_t addr, uint32_t srcaddr, uint32_t len)
+void fh_heap_copy(struct fh_thread_s *fh, uint32_t addr, uint32_t srcaddr, uint32_t len)
 {
-  memcpy(&fh->heap[addr], &fh->compile[srcaddr], len);
-}
-
-/** Reserve space in the compile memory area */
-enum fh_error fh_compile_reserve(
-    struct fh_thread_s *fh,
-    size_t len,
-    uint32_t *addr
-)
-{
-  uint32_t p = fh->compile_top; // FIXME this shouldn't be needed
-
-  if (p + len > COMPILED_BUFFER_SIZE) {
-    return FH_ERR_HEAP_FULL;
-  }
-
-  if (addr) {
-    *addr = p;
-  }
-
-  fh->compile_top = WORDALIGNED(p + len);
-
-  return FH_OK;
-}
-
-/** Write bytes to compile area at a given location. The region must have been previously allocated! */
-void fh_compile_write(struct fh_thread_s *fh, uint32_t addr, const void *src, uint32_t len)
-{
-  memcpy(&fh->compile[addr], src, len);
-}
-
-/** Allocate compile region and write bytes to it */
-enum fh_error fh_compile_put(struct fh_thread_s *fh, const void *src, uint32_t len)
-{
-  enum fh_error rv;
-  uint32_t addr;
-  TRY(fh_compile_reserve(fh, len, &addr));
-  fh_compile_write(fh, addr, src, len);
-  return FH_OK;
+  memcpy(&fh->heap[addr], &fh->heap[srcaddr], len);
 }
diff --git a/src/fh_runtime.c b/src/fh_runtime.c
index 004a17e..db662f1 100644
--- a/src/fh_runtime.c
+++ b/src/fh_runtime.c
@@ -93,7 +93,7 @@ enum fh_error w_user_word(struct fh_thread_s *fh, const struct fh_word_s *w0)
   }
   // make sure it's aligned
   fh->execptr = WORDALIGNED(fh->execptr);
-  const struct fh_instruction_s *instr = (const struct fh_instruction_s *) &fh->compile[fh->execptr];
+  const struct fh_instruction_s *instr = fh_instr_at(fh, fh->execptr);
   fh->execptr += INSTR_SIZE;
 
   uint32_t strl;
@@ -115,7 +115,7 @@ enum fh_error w_user_word(struct fh_thread_s *fh, const struct fh_word_s *w0)
         } else {
           LOG("Add postponed word: %s", w2->name);
           instr_init(&instr2, FH_INSTR_WORD, instr->data);
-          TRY(fh_compile_put(fh, &instr, INSTR_SIZE));
+          TRY(fh_heap_put(fh, &instr, INSTR_SIZE));
         }
       } else {
         LOGE("Postpone in interpret mode!");
@@ -169,13 +169,13 @@ enum fh_error w_user_word(struct fh_thread_s *fh, const struct fh_word_s *w0)
       strl = instr->data;
       if (instr->kind == FH_INSTR_ALLOCSTR) {
         TRY(fh_heap_reserve(fh, strl, &addr));
-        fh_heap_copy_from_compile(fh, addr, fh->execptr, strl);
-        LOG("Exec: alloc-str \"%.*s\"", strl, &fh->heap[addr]);
+        LOG("Exec: alloc-str \"%.*s\"", strl, fh_str_at(fh, fh->execptr));
+        fh_heap_copy(fh, addr, fh->execptr, strl);
         TRY(ds_push(fh, addr));
         TRY(ds_push(fh, strl));
       } else {
-        LOG("Exec: type-str \"%.*s\"", strl, &fh->compile[fh->execptr]);
-        FHPRINT("%.*s", (int) strl, &fh->compile[fh->execptr]);
+        LOG("Exec: type-str \"%.*s\"", strl, fh_str_at(fh, fh->execptr));
+        FHPRINT("%.*s", (int) strl, fh_str_at(fh, fh->execptr));
       }
       fh->execptr += strl;
       goto instr;
@@ -242,8 +242,8 @@ static enum fh_error fh_handle_quoted_string(
     } else {
       instr_init(&instr, FH_INSTR_TYPESTR, len);
     }
-    TRY(fh_compile_put(fh, &instr, INSTR_SIZE));
-    TRY(fh_compile_put(fh, start, len));
+    TRY(fh_heap_put(fh, &instr, INSTR_SIZE));
+    TRY(fh_heap_put(fh, start, len));
   }
   return FH_OK;
 }
@@ -255,7 +255,7 @@ enum fh_error fh_handle_word(struct fh_thread_s *fh, const struct fh_word_s *w)
   if (fh->state == FH_STATE_COMPILE && !w->immediate) {
     LOG("Compile word call: %s", w->name);
     instr_init(&instr, FH_INSTR_WORD, w->index);
-    TRY(fh_compile_put(fh, &instr, INSTR_SIZE));
+    TRY(fh_heap_put(fh, &instr, INSTR_SIZE));
   } else {
     /* interpret or immediate in compiled code */
     LOG("Run word: %s", w->name);
@@ -324,7 +324,7 @@ enum fh_error fh_handle_ascii_word(
   if (fh->state == FH_STATE_COMPILE) {
     LOG("Compile number: %ld", v);
     instr_init(&instr, FH_INSTR_NUMBER, (uint32_t) v);
-    TRY(fh_compile_put(fh, &instr, INSTR_SIZE));
+    TRY(fh_heap_put(fh, &instr, INSTR_SIZE));
   } else {
     /* interpret */
     LOG("Interpret number: %ld", v);
@@ -343,7 +343,7 @@ static void show_word(struct fh_thread_s *fh, const struct fh_word_s *w)
     // make sure it's aligned
     execptr = WORDALIGNED(execptr);
     FHPRINT("0x%08x: ", execptr);
-    const struct fh_instruction_s *instr = (const struct fh_instruction_s *) &fh->compile[execptr];
+    const struct fh_instruction_s *instr = fh_instr_at(fh, execptr);
     execptr += INSTR_SIZE;
 
     uint32_t strl;
@@ -385,10 +385,10 @@ static void show_word(struct fh_thread_s *fh, const struct fh_word_s *w)
       case FH_INSTR_TYPESTR:
         strl = instr->data;
         if (instr->kind == FH_INSTR_ALLOCSTR) {
-          FHPRINT("AllocStr(\"%.*s\")\n", strl, &fh->compile[execptr]);
+          FHPRINT("AllocStr(\"%.*s\")\n", strl, fh_str_at(fh, execptr));
           execptr += strl;
         } else {
-          FHPRINT("PrintStr(\"%.*s\")\n", strl, &fh->compile[execptr]);
+          FHPRINT("PrintStr(\"%.*s\")\n", strl, fh_str_at(fh, execptr));
           execptr += strl;
         }
         goto instr;
@@ -434,7 +434,7 @@ static enum fh_error fh_postpone_word(
   struct fh_instruction_s instr;
   LOG("Postpone %s", w->name);
   instr_init(&instr, FH_INSTR_POSTPONED_WORD, w->index);
-  TRY(fh_compile_put(fh, &instr, INSTR_SIZE));
+  TRY(fh_heap_put(fh, &instr, INSTR_SIZE));
 
   return FH_OK;
 }
diff --git a/src/main.c b/src/main.c
index d6278e0..621236d 100644
--- a/src/main.c
+++ b/src/main.c
@@ -84,9 +84,9 @@ int main(int argc, char *argv[])
   }
 
   // Show resource usage
-  LOG("\nResources used: DS %dW, RS %dW, CS %dW, heap %dB, program %dB, dict %dx\n",
+  LOG("\nResources used: DS %dW, RS %dW, CS %dW, memory %dB\n",
       (int) fh.data_stack_hwm, (int) fh.return_stack_hwm, (int) fh.control_stack_hwm,
-      (int) fh.heap_top, (int) fh.compile_top, (int) fh.dict_top);
+      (int) fh.here);
 
   FHPRINT_SVC("Bye.\n");
   return 0;