baseline

[rrq/rrqforth.git] / main.fasm

diff --git a/main.fasm b/main.fasm
index 6bd525a8e3e84c5daa0de659457879e28940e544..25e48b4f69a9aa1daf2561f2a24230d3f848a771 100644 (file)
--- a/main.fasm
+++ b/main.fasm
@@ -1,21 +1,79 @@
-; This is a program
+; This is a forth interpreter
        format elf64 executable
-       entry main
+       entry main_code
 
-       segment readable executable
-       msg db 'hello world.'
-       db 10
-       length = $ - msg
+;;; ############################################################
+;;; The FORTH words
+       segment readable writable executable
 
-main:
-       lea rsi,[msg]           ; address of message
-       mov edx,length          ; length od trdting
+include 'machine.fasm'
+       
+       ;; PROGRAM_VERSION is the program version string
+       WORD program_version, 'PROGRAM_VERSION', marker
+       db length
+program_version_string:        
+       include 'version'
+       length = $ - program_version_string
+       
+       ;; MAIN is the program entry point
+       ;; ( -- )
+       WORD_assembler main, "MAIN"
+       mov rsi,program_version_string ; address of string
+       mov edx,length          ; length of string (cheating)
        mov edi,1               ; stdout
        mov eax,1               ; sys_write
        syscall
+       jmp terminate0_code
 
-fini:
+       ;; TERMINATE0 terminates the program with code 0
+       ;; ( -- )
+       WORD_assembler terminate0, 'TERMINATE0'
        xor edi,edi
        mov eax,60
        syscall
+
+       ;; EXIT ends a forth code defintion, returning to caller
+       ;; ( -- )
+       WORD_assembler exit, 'EXIT'
+       popr rsi
+       next
        
+       ;; MARKER is a word that pushes the address after itself, then exits
+       ;; ( -- p )
+       WORD_assembler marker, 'MARKER'
+       push qword rsi
+       jmp exit_code
+
+       ;; MARKER@ is a word that pushes a the value after itself, then exits
+       ;; ( -- v )
+       WORD_assembler marker_get, 'MARKER@'
+       push qword [rsi]
+       jmp exit_code
+
+       ;; DOFORTH begins a FORTH defintion
+       WORD_assembler doforth, 'DOFORTH'
+       pushr rsi
+       lea rsi, [rax + 8]
+       next
+
+       ;; LIT is a word that pushes a the value after itself, then continues
+       ;; ( -- v )
+       WORD_assembler lit, 'LIT'
+       push qword [rsi]
+       add rsi, 8
+       next
+
+       ;; HERE is a variable pointing to the free heap
+       WORD here, 'HERE', marker
+       dq heap_start           ; initialise to first "free" data
+
+       ;; WORDS is the list of words
+       WORD words, 'WORDS', marker
+       dq forth_tfa            ; initialise to last forth word
+
+       ;; FORTH is the last word of the VOCABULARY 
+       WORD forth, 'FORTH', marker_get
+       dq forth_tfa
+       
+heap_start:
+