rc2014: aaalmost there...

Red 5 standing by.

drv/acia.fs

@@ -9,21 +9,12 @@ CONFIGURATION
 
 ACIA_CTL: IO port for the ACIA's control registers
 ACIA_IO: IO port for the ACIA's data registers
+ACIA_MEM: Address in memory that can be used variables shared
+          with ACIA's native words. 8 bytes used.
 )
 
 0x20 CONSTANT ACIABUFSZ
 
-( Points to ACIA buf )
-(sysv) ACIA(
-( Points to ACIA buf end )
-(sysv) ACIA)
-( Read buf pointer. Pre-inc )
-(sysv) ACIAR>
-( Write buf pointer. Post-inc )
-(sysv) ACIAW>
-( This means that if W> == R>, buffer is full.
-  If R>+1 == W>, buffer is empty. )
-
 : ACIA$
     H@ DUP DUP ACIA( ! ACIAR> !
     1 + ACIAW> ! ( write index starts one position later )
@@ -48,8 +39,9 @@ ACIA_IO: IO port for the ACIA's data registers
     ( As long as R> == W>-1, it means that buffer is empty )
     BEGIN ACIAR> @ 1 + ACIAW> @ = NOT UNTIL
 
-    ACIAR> @ C@
+    ( inc then fetch )
     1 ACIAR> +!
+    ACIAR> @ C@
 ;
 
 : EMIT

drv/acia.z80

@@ -1,8 +1,18 @@
-( Save ACIA ports from conf )
+( Save ACIA conf )
 ACIA_CTL
 : ACIA_CTL [ LITN ] ;
 ACIA_IO
 : ACIA_IO [ LITN ] ;
+( Points to ACIA buf )
+: ACIA( [ ACIA_MEM 4 + LITN ] ;
+( Points to ACIA buf end )
+: ACIA) [ ACIA_MEM 6 + LITN ] ;
+( Read buf pointer. Pre-inc )
+: ACIAR> [ ACIA_MEM LITN ] ;
+( Write buf pointer. Post-inc )
+: ACIAW> [ ACIA_MEM 2 + LITN ] ;
+( This means that if W> == R>, buffer is full.
+  If R>+1 == W>, buffer is empty. )
 
 (entry) ~ACIA
     AF PUSHqq,
@@ -14,26 +24,28 @@ ACIA_IO
     0x01 ANDn,   ( is ACIA rcv buf full? )
     JRZ, L2 FWR ( end, no, wrong interrupt cause. )
 
-    ACIAW> @ LDHL(nn),
+    ACIAW> LDHL(nn),
     ( is it == to ACIAR>? )
-    DE ACIAR> @ LDdd(nn),
+    DE ACIAR> LDdd(nn),
     ( carry cleared from ANDn above )
     DE SBCHLss,
     JRZ, L3 FWR ( end, buffer full )
 
+    DE ADDHLss, ( restore ACIAW> )
     ( buffer not full, let's write )
     ACIA_IO INAn,
     (HL) A LDrr,
 
     ( advance W> )
     HL INCss,
-    DE ACIAR) @ LDdd(nn),
+    ACIAW> LD(nn)HL,
+    DE ACIA) @ LDdd(nn),
     DE SUBHLss,
     JRNZ, L4 FWR ( skip )
     ( end of buffer reached )
     ACIA( @ LDHL(nn),
+    ACIAW> LD(nn)HL,
 L4 FSET ( skip )
-    ACIAW> @ LD(nn)HL,
 L3 FSET L2 FSET ( end )
 
     DE POPqq,

forth/notes.txt

@@ -115,7 +115,12 @@ those slots...) in boot binaries are made to jump to this address. If you use
 one of those slots for an interrupt, write a jump to the appropriate offset in
 that RAM location.
 
-SYSTEM SCRATCHPAD is reserved for temporary system storage.
+SYSTEM SCRATCHPAD is reserved for temporary system storage or can be reserved
+by low-level drivers. These are the current usages of this space throughout the
+project:
+
+* 0x51-0x53: (c<) pointer during in-memory initialization (see below)
+* 0x53-0x5b: ACIA buffer pointers in RC2014 recipes.
 
 *** Initialization sequence
 

recipes/rc2014/conf.fs

@@ -2,4 +2,5 @@
 0xf000 CONSTANT RS_ADDR
 0x80   CONSTANT ACIA_CTL
 0x81   CONSTANT ACIA_IO
+RAMSTART 0x53 + CONSTANT ACIA_MEM
 

recipes/rc2014/run.fs

@@ -3,7 +3,7 @@
     (c<$)
     ." Collapse OS" LF
     ( 0c == CINPTR )
-    ' (c<) 0x0c RAM+ !
+    ['] (c<) 0x0c RAM+ !
 ;
 INIT