;;; ============================================================
segment readable writable executable
-
-;;; This is the very first word
- ;; FORTH is the last word of WORDLIST FORTH
- WORD p_forth,'FORTH',dovalue
- ;; ( -- )
- ;; Change to use this wordlist
- dq last_forth_word
- dq inline_code
- mov rax,qword [p_forth_DFA]
- mov qword [p_wordlist],rax
- popr rsi
+;;; ========================================
+;;; These are the core "execution semantics" words, which are placed
+;;; first so as to remain at the same binary address at successive
+;;; compilations, which is helful for declaring special debugging gdb
+;;; aliases.
+;;;
+;;; The DO* words are declared as "variables" to provide their
+;;; assembled address when used in FORTH.
+;;;
+;;; The register context at entry to an "execution semantcs" code
+;;; snippets is:
+;;; rax = cfa* of word to execute
+;;; rsi = cell* in the calling definition, after calling cell
+;;; rsp = data stack pointer
+;;; rbp = return stack pointer
+;;;
+
+previous_word = 0 ; Used for chaining the words
+
+ WORD p_dofasm,'doFASM',dovariable
+ ;; Execution semantics for assembly words.
+dofasm:
+ add rax,8
+ jmp rax
+
+ WORD p_doforth,'doFORTH',dovariable ;
+ ;; Execution semantics for FORTH defition word.
+doforth:
+ pushr rsi
+ lea rsi, [rax+8] ; rsi = the DFA of the rax word
next
- WORD p_syscall,'SYSCALL',dodoes,,,8
- ;; ( -- )
- ;; Change to use this wordlist
- dq last_syscall_word
- dq inline_code
- mov rax,qword [p_syscall_DFA]
- mov qword [p_wordlist],rax
- popr rsi
+ WORD p_dodoes,'doDOES',dovariable
+ ;; Execution semantics for DOES>
+ ;; [cfa-8] holds the adjustment offset ("does offset")
+dodoes:
+ pushr rsi
+ lea rsi, [rax+8] ; rsi = the DFA of the rax word
+ add rsi,qword [rax-8] ; adjust rsi by the "does offset'
next
-last_wordlists_word:
- WORD p_wordlists,'WORDLISTS',dodoes,,,8
- ;; ( -- )
- ;; Change to use this wordlist
- dq p_wordlists_TFA
- dq inline_code
- mov rax,qword [p_wordlists_DFA]
- mov qword [p_wordlist],rax
- popr rsi
+ WORD p_dovariable,'doVARIABLE',dovariable
+ ;; Execution semantics for a variable ( -- addr )
+ ;; rax points to CFA field
+dovariable:
+ lea rax, [rax+8] ; rsi = the DFA of the rax word
+ push rax
next
+
+ WORD p_dovalue,'doVALUE',dovariable
+ ;; Execution semantics for a value constant ( -- v )
+ ;; rax points to CFA field
+dovalue:
+ lea rax, [rax+8] ; rsi = the DFA of the rax word
+ push qword [rax]
+ next
+
+ WORD p_dostring,'doSTRING',dovariable
+ ;; Execution semantics for a string constant ( -- addr n )
+ ;; rax points to CFA field
+dostring:
+ lea rax, [rax+8] ; rsi = the DFA of the rax word
+ pushpname rax
+ next
+
+include 'syscalls.asm'
+
+;;; ========================================
+;;; The stacks are placed here.
-include 'wordlists.asm'
+ ;segment readable writable
- WORD return_stack,'RS',dovariable
+ WORD return_stack,'RETURN-STACK',dovariable
;; The return stack
+ BLOCK RS_TOP
rb 1048576 ; 1 Mb return stack
RS_TOP: ; The initial rbp
- WORD data_stack,'DS',dovariable
+last_system_word:
+ WORD data_stack,'DATA-STACK',dovariable
;; The data stack
+ BLOCK DS_TOP
rb 1048576 ; 1 Mb data stack
DS_TOP: ; The initial rsp
+
+;;; ========================================
+;;; Core execution control words
+
+ ;segment readable executable
+
+;;; At fasm compilation: reset previous_word to make a new word list
+;;; Words above belong to the SYSTEM wordlist, and the following
+;;; belong to the FORTH wordlist.
+previous_word = 0
+
+ WORD p_system,'SYSTEM',dovariable
+ ;; ( -- dfa )
+ ;; The SYSTEM word list
+ dq last_system_word ; tfa of last SYSTEM word
+ dq p_forth_DFA ; dfa of successor word list
+
WORD inline_code,'[ASM]',fasm
;; ( -- )
;; This transitions execution into inline assembler in the
;; exit to the calling definition via "jmp exit".
jmp qword rsi
+ WORD p_execute,'EXECUTE',fasm
+ ;; ( tfa -- )
+ ;; Execute the word
+ pop rax
+ tfa2cfa rax
+ jmp qword [rax] ; goto code of that FORTH word (64 bit jump)
+
WORD p_exit, 'EXIT',fasm
;; ( -- ) ( R: addr -- )
;; Returns execution to the calling definition as per the
;; TERMINATE0 terminates the program with code 0
;; ( -- )
- WORD terminate, 'TERMINATE0',fasm
+ WORD p_terminate, 'TERMINATE0',fasm
pop rdx
terminate_special:
mov eax,60
syscall
-;;; 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
-;;; this word.
-doforth:
- pushr rsi
- lea rsi, [rax+8] ; rsi = the DFA of the rax word
- next
-
-;;; 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 CFA field
-dovariable:
- add rax,8
- push rax
+ WORD p_branch,'BRANCH',fasm
+ ;; ( -- )
+ ;; Using subsequent inline cell as branch offset, branch
+ ;; accordingly
+ add rsi,qword [rsi]
+ add rsi,8
next
-
- ;; Execution semantics for a constant ( -- v )
- ;; rax points to CFA field
-dovalue:
- push qword [rax+8]
+
+ WORD p_zero_branch,'0BRANCH',fasm
+ ;; ( v -- )
+ ;; Using subsequent inline cell as branch offset, branch
+ ;; accordingly if the stacked value is zero, otherwise just
+ ;; skip over the branch offset
+ pop rax
+ cmp rax,0
+ jne p_zero_branch_SKIP
+ add rsi,qword [rsi]
+p_zero_branch_SKIP:
+ add rsi,8
next
- ;; Execution semantics for a string constant ( -- addr n )
- ;; rax points to CFA field
-dostring:
- cfa2dfa rax
- pushpname rax
- next
+;;; ========================================
+;;; Core extension(s)
+ ;segment readable writable executable
+
+include 'wordlists.asm'
include 'memory.asm'
include 'stack.asm'
include 'math.asm'
+include 'logic.asm'
include 'stdio.asm'
include 'compile.asm'
main:
mov rsp,DS_TOP
mov rbp,RS_TOP
- ;; Initialize STREAM STDIN
+ cmp qword [p_stdin_DFA],0
+ jne p_quit_INITIALIZED
+ ;; Initialize STDIN
push 0
push 10000
DOFORTH p_stream
- pop qword [p_stdin_DFA]
+ pop qword [p_stdin_DFA] ; Assign STDIN
+p_quit_INITIALIZED:
;; Initial blurb
FORTH
dq p_program_version
dq p_tell
dq p_stdin
- dq p_read_word
+ dq p_clear_stream
+ dq p_stdin
+ dq p_evaluate_stream
+ BRANCH 0,p_quit_ERROR
+ dq p_false
+ dq sys_exit
+p_quit_ERROR:
+ dq p_literal_string
+ STRING 10,'*** Unknown word: '
+ dq p_tell
+ dq p_this_word
+ dq p_2get
+ dq p_tell
+ dq p_literal_string
+ STRING 10
dq p_tell
- dq p_nl
- dq p_emit
ENDFORTH
-
- ;; DOFORTH p_words
-
- push 0
- DOFORTH sys_exit
+ mov rbp,RS_TOP ; reset the return stack
+ jmp main
- previous_word = last_wordlists_word
+;;; ========================================
-include 'syscalls.asm'
-
-
-last_word:
+ ;segment readable writable
heap_start:
rb 1048576 ; +1 Mb heap
rb 1048576 ; +1 Mb heap
rb 1048576 ; +1 Mb heap
+ rb 1048576 ; +1 Mb heap
+ rb 1048576 ; +1 Mb heap