First tests with Y=TOS and CPU flags

TG9541 · Dec 7, 2016 · 03996fb · 03996fb
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diff --git a/README.md b/README.md
@@ -1,35 +1,36 @@
 # STM8S eForth (stm8ef)
 
-This is a heavily refactored port of Dr. C.H. Ting's eForth for the *STM8S Discovery* to STM8S *Value Line* µCs boards and the [SDCC toolchain](http://sdcc.sourceforge.net/). Mixing C, Forth, and assembler is possible.
+This is an extended and refactored version of [Dr. C.H. Ting's eForth for the *STM8S Discovery*](http://www.forth.org/svfig/kk/07-2010.html) that turns STM8S *Value Line* µCs boards into an interactive Forth development environment. The [SDCC toolchain](http://sdcc.sourceforge.net/) is used for building the eForth core, which makes mixing Forth, assembly, and C possible.
 
-The binary of the core interactive Forth system uses below 4400 bytes, including the overhead from SDCC, like C startup code, and interrupt tables. The binary size with a rich feature feature set, including *Compile to Flash*, *Background Task*, and *CREATE-DOES>* is below 5000 bytes!
+The binary of an interactive eForth system uses below 4400 bytes, including the overhead from SDCC (C startup code and interrupt table). With a rich feature feature set (*Compile to Flash*, *Background Task*, and *CREATE-DOES>*) the binary size is below 5000 bytes.
 
 Please refer to the [Wiki on GitHub](https://github.com/TG9541/stm8ef/wiki) for more information! 
 
 ## Overview
 
-New features:
+Features:
 
-* compile Forth to Non Volatile Memory (Flash IAP)
-* preemotive background tasks for concurrent `INPUT-PROCESS-OUTPUT` processing with a fixed cycle time (5ms using TIM2)
+* compile Forth to NVM (Non Volatile Memory with Flash IAP)
+* autostart feature for embedded applications
+* preemptive background tasks, e.g. for `INPUT-PROCESS-OUTPUT` proces with fixed cycle time (default 5ms)
 * *CREATE-DOES>* pattern
 * configurable vocabulary subsets for binary size reduction
 * Extended vocabulary:
   * STM8 ADC control: ADC! ADC@ 
   * board keys, outputs, LEDs: OUT OUT!
   * EEPROM, FLASH lock/unlock: LOCK ULOCK LOCKF ULOCKF
   * native bit set/reset: BSR  
-  * inverted byte order 16bit register access: BSR 2C@ 2C! 
-  * compile to Flash memory: NVR RAM RESET 'BOOT
+  * inverted byte order 16bit register access: 2C@ 2C! 
+  * compile to Flash memory: NVR RAM RESET
+  * autostart applications: 'BOOT
   * ASCII file transfer: FILE HAND
-* STC with native BRANCH and EXIT
-* board support:
+* Subroutine Threaded Code (STC) with native BRANCH and EXIT
+* board supporti for Chinese made [STM8S based very low cost boards][WG1]:
   * W1209 LED display & half-duplex with SW TX 
   * C0135 Relay-4 Board
   * STM8S103F3 "$0.70" breakout board
 * support for [boards with 7Seg-LED UI](https://github.com/TG9541/stm8ef/wiki/eForth-Background-Task): in a background task, `123 .` goes to the 7Seg-LED display, and `?KEY` reads board keys
 
-Many changes to the original source are due to "board support" for Chinese made [STM8S based very low cost boards][WG1].
 
 Canges that required refactoring the original code:
 
@@ -62,7 +63,7 @@ There is board suport for some easily available "Chinese gadgets". For details,
 * `BOARD_W1209` W1209 low cost thermostat with LED display and half-duplex RS232 through sensor header (9600 baud) 
 * `BOARD_C0135` C0135 "Relay-4 Board" (can be used as a *Nano PLC*)
 
-There is currently no support for the STM8S Discovery, since I don't have STM8S105C6T6 based boards for testing.
+Currently, there is no support for the STM8S Discovery, since I don't have any STM8S105C6T6 based boards for testing.
 
 ### STM8S003F3 Core
 

diff --git a/forth.asm b/forth.asm
@@ -858,7 +858,7 @@ STORE:
 	ADDW    X,#4            ; store w at a
 	RET	
 
-;	@	( a -- w )
+
 ;	Push memory location to stack.
 
 	.dw	LINK
@@ -887,7 +887,7 @@ CSTOR:
 	ADDW    X,#4
 	RET	
 
-;	C@	( b -- c )
+;	C@	( b -- c )      ; C@ sets Z and N
 ;	Push byte in memory to	stack.
 
 	.dw	LINK
@@ -898,8 +898,8 @@ CAT:
 	LDW     Y,X	        ; Y=b
 	LDW     Y,(Y)
 	LD      A,(Y)
-	LD      (1,X),A
 	CLR     (X)
+	LD      (1,X),A
 	RET	
 
         .ifne   WORDS_EXTRASTACK
@@ -2174,20 +2174,15 @@ TWOSL:
 	.ascii	">CHAR"
 	.endif
 TCHAR:
-	CALL	DOLITC
-	.db	0x07F
-	CALL	ANDD
-	CALL	DUPP	;mask msb
-	CALL	DOLITC
-	.db	127
-	CALL	BLANK
-	CALL	WITHI	;check for printable
-	CALL	QBRAN
-	.dw	TCHA1
-	CALL	DROP
-	CALL	DOLITC
-	.db	0x05F	; "_"	;replace non-printables
-TCHA1:	RET
+        LD      A,(1,X)
+        AND     A,#0x7F
+        CP      A,#0x7F
+        JREQ    1$
+        CP      A,#(' ')
+        JRUGE   2$
+1$:     LD      A,#('_')
+2$:     LD      (1,X),A
+        RET
 
 ;	DEPTH	( -- n )
 ;	Return	depth of data stack.
@@ -2361,12 +2356,11 @@ PAD:
 	.ascii	"@EXECUTE"
         .endif        
 ATEXE:
-	CALL	AT
-	CALL	QDUP	;?address or zero
-	CALL	QBRAN
-	.dw	EXE1
-	CALL	EXECU	;execute if non-zero
-EXE1:	RET	;do nothing if zero
+	CALL	AT              ; @ sets Z and N
+        JRNE    1$
+        JP      DROP
+1$:	JP	EXECU	        ; execute if non-zero
+
 
 ;	CMOVE	( b1 b2 u -- )
 ;	Copy u bytes from b1 to b2.
@@ -4370,9 +4364,9 @@ DOESS:
 	.ascii	"dodoes"
         .endif
 DODOES:
-        CALL    LAST
+        CALL    LAST                   ; ( link field of current word )
         CALL    AT
-        CALL    NAMET                  ; ' ( 'last call nop )
+        CALL    NAMET                  ; ' ( 'last  )
         CALL    DOLITC
         .db     BRAN_OPC               ; ' JP
         CALL    OVER                   ; ' JP '
@@ -4622,18 +4616,16 @@ SEE4:	CALL	NUFQ	;user control
 	.ascii	"WORDS"
 WORDS:
 	CALL	CR
-	CALL	CNTXT	;only in context
-WORS1:	CALL	AT
-	CALL	QDUP	;?at end of list
-	CALL	QBRAN
-	.dw	WORS2
+	CALL	CNTXT	        ; only in context
+WORS1:	CALL	AT              ; @ sets Z and N
+        JREQ    1$              ; ?at end of list
 	CALL	DUPP
 	CALL	SPACE
-	CALL	DOTID	;display a name
+	CALL	DOTID	        ; display a name
 	CALL	CELLM
         JRA     WORS1
-	CALL	DROP
-WORS2:	RET
+1$:	CALL	DROP
+	RET
 
 	
 ;