Refer to BOOT and (uflw) by addr in stable ABI

Was previously referred to by name+find, which was wasteful.

blk/089

@@ -6,9 +6,9 @@ very few things.
 1. Set SP to PS_ADDR and IX to RS_ADDR
 2. Sets HERE to RAMEND (RAMSTART+0x80).
 3. Sets CURRENT to value of LATEST field in stable ABI.
-4. Look for the word "BOOT" and calls it.
+4. Execute the word referred to by 0x04 (BOOT) in stable ABI.
 
-In a normal system, BOOT is in xcomp core (B411) and does a
+In a normal system, BOOT is in core words at B396 and does a
 few things:
 
 1. Initialize all overrides to 0.

blk/283

@@ -1,6 +1,6 @@
 H@ ORG !
-0 JPnn, ( 00, main ) NOP, NOP, NOP, ( unused )
-NOP, NOP, ( unused ) NOP, NOP, ( 08, LATEST )
+0 JPnn, ( 00, main ) NOP, ( unused ) NOP, NOP, ( 04, BOOT )
+NOP, NOP, ( 06, uflw ) NOP, NOP, ( 08, LATEST )
 NOP, NOP, NOP, NOP, NOP, NOP, NOP, ( 0a, unused )
 0 JPnn, ( 11, pushRS ) 0 JPnn, ( 14, popRS )
 NOP, NOP, NOP, ( unused )

blk/298

@@ -1,8 +1,5 @@
-6 A, '(' A, 'u' A, 'f' A, 'l' A, 'w' A, ')' A,
 lblofl BSET ( abortUnderflow )
-    HL PC 7 - LDddnn,
-    DE RAMSTART 0x02 + LDdd(nn),   ( RAM+02 == CURRENT )
-    lblfind @ CALLnn,
+    DE BIN( @ 0x06 ( uflw ) + LDdd(nn),
     JR, L2 FWR ( execute, B301 )
 
 

blk/299

@@ -1,4 +1,3 @@
-L1 BSET 4 A, 'B' A, 'O' A, 'O' A, 'T' A,
 PC ORG @ 1 + ! ( main )
 ( STACK OVERFLOW PROTECTION: See B76 )
     SP PS_ADDR LDddnn, IX RS_ADDR LDddnn,
@@ -10,7 +9,5 @@ PC ORG @ 1 + ! ( main )
   Forth. )
     BIN( @ 0x08 + LDHL(nn),
     RAMSTART 0x02 ( CURRENT ) + LD(nn)HL,
-    EXDEHL,
-    HL L1 @ LDddnn,
-    lblfind @ CALLnn,
+    DE BIN( @ 0x04 ( BOOT ) + LDdd(nn),
     JR, L1 FWR ( execute, B301 )

blk/381

@@ -6,6 +6,7 @@
 : CRLF CR LF ; : SPC 32 EMIT ;
 : NL 0x0a RAM+ @ ( NLPTR ) ?DUP IF EXECUTE ELSE CRLF THEN ;
 : (uflw) LIT" stack underflow" ERR ;
+XCURRENT @ _xapply ORG @ 0x06 ( stable ABI uflw ) + !
 : (wnf) (print) SPC LIT" word not found" ERR ;
 
 

blk/396

@@ -13,4 +13,4 @@
     1 0x06 RAM+ ! INTERPRET
     RDLN$ LIT< _sys [entry]
     LIT< CollapseOS (print) NL (main) ;
-
+XCURRENT @ _xapply ORG @ 0x04 ( stable ABI BOOT ) + !

blk/821

@@ -1,4 +1,3 @@
-L3 BSET 4 A, 'B' A, 'O' A, 'O' A, 'T' A,
 PC 3 - ORG @ 1+ ! ( main )
     SP PS_ADDR MOVxI, BP RS_ADDR MOVxI,
     DI 0x08 MOVxm, ( LATEST )
@@ -6,8 +5,5 @@ PC 3 - ORG @ 1+ ! ( main )
     BX RAMSTART MOVxI,
     [BX] 0x04 ( HERE ) DI MOV[]+x,
     [BX] 0x02 ( CURRENT ) DI MOV[]+x,
-    SI L3 @ MOVxI,
-    CALLn, lblfind @ RPCn, ( find )
-    IFZ, JMPn, lblexec @ RPCn, ( execute ) THEN,
-    AH 0x0e MOVri, ( print char ) AL '!' MOVri, 0x10 INT,
-    BEGIN, JMPs, AGAIN,
+    DI 0x04 ( BOOT ) MOVxm,
+    JMPn, lblexec @ RPCn, ( execute )