From: Ralph Ronnquist <ralph.ronnquist@gmail.com>
Date: Tue, 18 May 2021 05:18:27 +0000 (+1000)
Subject: added short string macro
X-Git-Url: https://git.rrq.au/?a=commitdiff_plain;h=69125f1514739aa5dcee13a29eb161a229e47eed;p=rrq%2Frrqforth.git

added short string macro
---

diff --git a/machine.asm b/machine.asm
index 058da15..a8bfbd8 100644
--- a/machine.asm
+++ b/machine.asm
@@ -142,7 +142,7 @@ label#_DFA:
 }
 
 ;;; ========================================
-;;; The block macro lays out the length for a subsequent block to the
+;;; The BLOCK macro lays out the length for a subsequent block to the
 ;;; given label.
 macro BLOCK endlabel {
 	local datastart
@@ -150,3 +150,16 @@ macro BLOCK endlabel {
 datastart:
 	}
 
+;;; ========================================
+;;; The STRING macro lays out length byte and data for s short string
+macro STRING [data] {
+common
+	local datastart, dataend
+	db dataend - datastart
+datastart:
+forward
+	db data
+common
+dataend:
+	}
+
diff --git a/rrqforth.asm b/rrqforth.asm
index 41bab41..9709fde 100644
--- a/rrqforth.asm
+++ b/rrqforth.asm
@@ -26,6 +26,14 @@ DS_TOP:				; The initial rsp
 	;; exit to the calling definition via "jmp exit".
 	jmp qword rsi
 
+	WORD p_exit, 'EXIT',fasm
+	;; ( -- ) ( R: addr -- )
+	;; Returns execution to the calling definition as per the
+	;; return stack.
+exit:
+	popr rsi
+	next
+
 ;;; Execution semantics for FORTH defition word
 ;;; At entry, rsi points into the calling definition, at the cell
 ;;; following the cell indicating this word, rax points to the CFA of
@@ -35,33 +43,36 @@ doforth:
 	lea rsi, [rax+8] 	; rsi = the DFA of the rax word
 	next
 
-	WORD p_exit, 'EXIT',fasm
-	;; ( -- ) ( R: addr -- )
-	;; Returns execution to the calling definition as per the
-	;; return stack.
-exit:
-	popr rsi
+;;; Execution semantics for DOES>
+;;; The cell at [cfa-8] holds an adjustment offset.
+dodoes:
+	pushr rsi
+	lea rsi, [rax+8] 	; rsi = the DFA of the rax word
+	add rsi,[rax-8]		; adjust rsi to the DOES> part
 	next
 
 	;; Execution semantics for a variable ( -- addr )
-	;; rax points to doer field
+	;; rax points to CFA field
 dovariable:
-	push rax+16
+	add rax,8
+	push rax
 	next
 
 	;; Execution semantics for a constant ( -- v )
-	;; rax points to doer field
+	;; rax points to CFA field
 dovalue:
-	push qword [rax+16]
+	push qword [rax+8]
 	next
 
 	;; Execution semantics for a string constant ( -- addr n )
-	;; rax points to doer field
+	;; rax points to CFA field
 dostring:
-	add rax,16
+	add rax,8
+	xor rbx,rbx
 	mov bl,[rax]
-	mov byte [rsp],bl
-	push rax+1
+	inc rax
+	push rax
+	push rbx
 	next
 
 include 'wordlists.asm'
@@ -72,10 +83,7 @@ include 'math.asm'
 include 'stdio.asm'
 
 	WORD p_program_version,'PROGRAM_VERSION',dostring
-	db length
-program_version_string:	
-	db 'RRQ Forth version 0.1 - 2021-05-13',10
-	length = $ - program_version_string
+	STRING 'RRQ Forth version 0.1 - 2021-05-13',10
 
 	WORD p_stdin,'STDIN',dovalue
 	;; Initialised to hold a STREAM for fd 0
@@ -101,8 +109,7 @@ main:
 	ENDFORTH
 
 	push qword 1			; stdout
-	push qword program_version_string ; address of string
-	push qword length 		; length of string (cheating)
+	DOFORTH p_program_version	; version string => ( s n )
 	DOFORTH sys_write		; printout
 	pop rax				; ignore errors