diff --git a/blk/208 b/blk/208
index f58784c..da7f2fb 100644
--- a/blk/208
+++ b/blk/208
@@ -5,7 +5,7 @@ d => BC DE HL AF/SP
 c => CNZ CZ CNC CC CPO CPE CP CM
 
 LD [rr, ri, di, (i)HL, HL(i), d(i), (i)d, rIXY, IXYr,
-    (DE)A, A(DE)]
+    (DE)A, A(DE), (i)A, A(i)]
 ADD [r, i, HLd, IXd, IXIX, IYd, IYIY]
 ADC [r, HLd]
 CP  [r, i, (IXY+)]
diff --git a/blk/240 b/blk/240
index 0899b83..43405eb 100644
--- a/blk/240
+++ b/blk/240
@@ -7,5 +7,5 @@
 ;
 0xcd OP3n CALL,
 0xc3 OP3n JP,
-0x22 OP3n LD(n)HL,
-0x2a OP3n LDHL(n),
+0x22 OP3n LD(n)HL,             0x2a OP3n LDHL(n),
+0x32 OP3n LD(i)A,              0x3a OP3n LDA(i),
diff --git a/blk/582 b/blk/582
index ff03915..fa6f941 100644
--- a/blk/582
+++ b/blk/582
@@ -1,15 +1,14 @@
 0x80 CONSTANT ACIA_CTL ( IO port for ACIA's control register )
 0x81 CONSTANT ACIA_IO ( IO port for ACIA's data registers )
+0x20 CONSTANT ACIA_BUFSZ ( SZ-1 must be a mask )
 ( Address in memory that can be used variables shared
-  with ACIA's native words. 8 bytes used. )
+  with ACIA's native words. 4 bytes used. )
 CREATE ACIA_MEM SYSVARS 0x70 + ,
 ( Points to ACIA buf )
-: ACIA( ACIA_MEM @ 4 + ;
-( Points to ACIA buf end )
-: ACIA) ACIA_MEM @ 6 + ;
-( Read buf pointer. Pre-inc )
+: ACIA( ACIA_MEM @ 2+ ;
+( Read buf idx Pre-inc )
 : ACIAR> ACIA_MEM @ ;
-( Write buf pointer. Post-inc )
-: ACIAW> ACIA_MEM @ 2+ ;
+( Write buf idx Post-inc )
+: ACIAW> ACIA_MEM @ 1+ ;
 ( This means that if W> == R>, buffer is full.
   If R>+1 == W>, buffer is empty. )
diff --git a/blk/583 b/blk/583
index e979cf1..153f0ec 100644
--- a/blk/583
+++ b/blk/583
@@ -1,13 +1,16 @@
-(entry) ~ACIA ( Set RST 38 jump ) PC ORG @ 0x39 + !
-    AF PUSH, HL PUSH, DE PUSH,
-	( Read our character from ACIA into our BUFIDX )
-    ACIA_CTL INAi,
-    0x01 ANDi,   ( is ACIA rcv buf full? )
-    IFNZ,
-        ( correct interrupt cause )
-        ACIAW> LDHL(n),
-        ( is it == to ACIAR>? )
-        ( +0 == ACIAR> )
-        DE ACIAR> LDd(n),
-        ( carry cleared from ANDi above )
-        DE SBCHLd,                                    ( cont. )
+( ACIA INT handler, read into ACIAW> )
+( Set RST 38 jump ) PC ORG @ 0x39 + !
+    AF PUSH,
+    ACIA_CTL INAi, 0x01 ANDi, ( is ACIA rcv buf full? )
+    IFZ, ( no, abort ) AF POP, EI, RETI, THEN,
+    HL PUSH,
+    HL ACIAW> LDdn, A (HL) LDrr,
+    HL DECd, (HL) CPr, ( W> == R> ? )
+    IFNZ, ( buffer not full )
+        ( get wr ptr ) HL ACIA( LDd(n),
+        L ADDr, IFC, H INCr, THEN, L A LDrr,
+        ( fetch/write ) ACIA_IO INAi, (HL) A LDrr,
+        ( advance W> ) ACIAW> LDA(i), A INCr,
+        ACIA_BUFSZ 1- ANDi, ACIAW> LD(i)A,
+    THEN,
+    HL POP, AF POP, EI, RETI,
diff --git a/blk/584 b/blk/584
deleted file mode 100644
index 7e9defa..0000000
--- a/blk/584
+++ /dev/null
@@ -1,14 +0,0 @@
-        IFNZ, ( buffer full? )
-            ( no, continue )
-            DE ADDHLd, ( restore ACIAW> )
-            ( buffer not full, let's write )
-            ACIA_IO INAi,
-            (HL) A LDrr,
-            ( advance W> )
-            HL INCd,
-            ACIAW> LD(n)HL,
-            DE ACIA) LDd(n),
-            DE SUBHLd,
-
-
-                                                      ( cont. )
diff --git a/blk/585 b/blk/585
deleted file mode 100644
index f8b5738..0000000
--- a/blk/585
+++ /dev/null
@@ -1,9 +0,0 @@
-            IFZ, ( end of buffer reached? )
-                ( yes )
-                ACIA( LDHL(n),
-                ACIAW> LD(n)HL,
-            THEN,
-        THEN,
-    THEN,
-    DE POP, HL POP, AF POP,
-    EI, RETI,
diff --git a/blk/587 b/blk/587
index 9b91d38..d8c58e2 100644
--- a/blk/587
+++ b/blk/587
@@ -1,12 +1,10 @@
 : (key)
     ( inc then fetch )
-    [ ACIAR> LITN ] @ 1+ DUP [ ACIA) LITN ] @ = IF
-        DROP [ ACIA( LITN ] @
-    THEN
+    [ ACIAR> LITN ] C@ 1+ [ ACIA_BUFSZ 1- LITN ] AND
     ( As long as R> == W>-1, it means that buffer is empty )
-    BEGIN DUP [ ACIAW> LITN ] @ = NOT UNTIL
-    [ ACIAR> LITN ] !
-    [ ACIAR> LITN ] @ C@
+    BEGIN DUP [ ACIAW> LITN ] C@ = NOT UNTIL
+    DUP [ ACIA( LITN ] @ + C@ ( ridx c )
+    SWAP [ ACIAR> LITN ] C! ( c )
 ;
 : (emit)
     ( As long at CTL bit 1 is low, we are transmitting. wait )
diff --git a/blk/588 b/blk/588
index 7b11043..6ac8ded 100644
--- a/blk/588
+++ b/blk/588
@@ -1,8 +1,7 @@
 : ACIA$
-    H@ DUP DUP [ ACIA( LITN ] ! [ ACIAR> LITN ] !
-    1+ [ ACIAW> LITN ] ! ( write index starts one pos later )
-    0x20 ( buffer size ) ALLOT
-    H@ [ ACIA) LITN ] !
+    H@ [ ACIA( LITN ] ! 0 [ ACIAR> LITN ] C!
+    1 [ ACIAW> LITN ] C! ( write index starts one pos later )
+    [ ACIA_BUFSZ LITN ] ALLOT
 ( setup ACIA
   CR7 (1) - Receive Interrupt enabled
   CR6:5 (00) - RTS low, transmit interrupt disabled.