X-Git-Url: https://git.rrq.au/?a=blobdiff_plain;f=main.asm;h=e6b0ac280cfc359bbad93881900df086e3e0379e;hb=4d233157714c21c1c15e7b271460a1692da55f52;hp=d0c43917ae4971d8961f3d6b02d9030b95c90753;hpb=1013709c277143b58deafcf9a1faccd3e9b799a2;p=rrq%2Fjonasforth.git

diff --git a/main.asm b/main.asm
index d0c4391..e6b0ac2 100644
--- a/main.asm
+++ b/main.asm
@@ -32,11 +32,16 @@ macro popr x {
 ;;
 ;; This macro also defines a label LABEL_entry.
 initial_latest_entry = 0
-macro header label, name {
+macro header label, name, immediate {
   local .string_end
 
 label#_entry:
   dq initial_latest_entry
+  if immediate eq
+    db 0
+  else
+    db 1
+  end if
   db .string_end - ($ + 1)
   db name
   .string_end:
@@ -46,16 +51,16 @@ initial_latest_entry = label#_entry
 }
 
 ;; Define a Forth word that is implemented in assembly. See 'header' for details.
-macro forth_asm label, name {
-  header label, name
+macro forth_asm label, name, immediate {
+  header label, name, immediate
   dq .start
 .start:
 }
 
 ;; Define a Forth word that is implemented in Forth. (The body will be a list of
 ;; 'dq' statements.)
-macro forth label, name {
-  header label, name
+macro forth label, name, immediate {
+  header label, name, immediate
   dq DOCOL
 }
 
@@ -117,7 +122,7 @@ forth_asm FIND, 'FIND'
 ;; entry.
 forth_asm TCFA, '>CFA'
   pop rax
-  add rax, 8                    ; [rax] = length of name
+  add rax, 8 + 1                ; [rax] = length of name
   movzx rbx, byte [rax]
   inc rax
   add rax, rbx                  ; [rax] = codeword
@@ -193,8 +198,8 @@ forth_asm READ_WORD, 'READ-WORD'
 ;; Takes a string on the stack and replaces it with the decimal number that the
 ;; string represents.
 forth_asm PARSE_NUMBER, 'PARSE-NUMBER'
-  pop [parse_number.length]     ; Length
-  pop [parse_number.buffer]     ; String pointer
+  pop rcx     ; Length
+  pop rdi     ; String pointer
 
   push rsi
   call parse_number
@@ -263,8 +268,19 @@ forth_asm DROP, 'DROP'
   add rsp, 8
   next
 
+forth_asm NOT_, 'NOT'
+  pop rax
+  cmp rax, 0
+  jz .false
+.true:
+  push 0
+  next
+.false:
+  push 1
+  next
+
 ;; The INTERPRET word reads and interprets user input. It's behavior depends on
-;; the current STATE. It provides special handling for integers. (TODO)
+;; the current STATE. It provides special handling for integers.
 forth INTERPRET, 'INTERPRET'
   ;; Read word
   dq READ_WORD
@@ -272,9 +288,22 @@ forth INTERPRET, 'INTERPRET'
   ;; Stack is (word length word length).
   dq FIND                       ; Try to find word
   dq DUP_
-  dq ZBRANCH, 8 * 8             ; Check if word is found
+  dq ZBRANCH, 8 * 20            ; Check if word is found
+
+  ;; - Word is found -
+
+  dq STATE, GET, ZBRANCH, 8 * 9 ; Check whether we are in compilation or immediate mode
+
+  ;; (Word found, compilation mode)
+  dq DUP_, IS_IMMEDIATE, NOT_, ZBRANCH, 8 * 4 ; If the word is immediate, continue as we would in immediate mode
+
+  ;; Otherwise, we want to compile this word
+  dq TCFA
+  dq COMMA
+  dq EXIT
 
-  ;; Word is found, execute it
+  ;; (Word found, immediate mode)
+  ;; Execute word
   dq TCFA
   ;; Stack is (word length addr)
   dq SWAP, DROP
@@ -283,10 +312,19 @@ forth INTERPRET, 'INTERPRET'
   dq EXEC
   dq EXIT
 
-  ;; No word is found, assume it is an integer literal
+  ;; - No word is found, assume it is an integer literal -
   ;; Stack is (word length addr)
   dq DROP
   dq PARSE_NUMBER
+
+  dq STATE, GET, ZBRANCH, 8 * 5 ; Check whether we are in compilation or immediate mode
+
+  ;; (Number, compilation mode)
+  dq LIT, LIT, COMMA
+  dq COMMA
+  dq EXIT
+
+  ;; (Number, immediate mode)
   dq EXIT
 
 ;; .U prints the value on the stack as an unsigned integer in hexadecimal.
@@ -364,6 +402,18 @@ forth_asm GET, '@'
   push rax
   next
 
+forth_asm PUT_BYTE, 'C!'
+  pop rbx
+  pop rax                       ; Value
+  mov [rbx], al
+  next
+
+forth_asm GET_BYTE, 'C@'
+  pop rax
+  movzx rax, byte [rax]
+  push rax
+  next
+
 ;; Add two integers on the stack.
 forth_asm PLUS, '+'
   pop rax
@@ -381,6 +431,17 @@ forth_asm MINUS, '-'
   push rbx
   next
 
+;; Given two integers a and b on the stack, pushes the quotient and remainder of
+;; division of a by b.
+forth_asm TIMESMOD, '/MOD'
+  pop rbx                       ; b
+  pop rax                       ; a
+  mov rdx, 0
+  div rbx
+  push rax                      ; a / b
+  push rdx                      ; a % b
+  next
+
 ;; Get the location of the STATE variable. It can be set with '!' and read with
 ;; '@'.
 forth STATE, 'STATE'
@@ -454,7 +515,10 @@ forth_asm CREATE, 'CREATE'
   mov [latest_entry], rdi       ; Update LATEST to point to this word
 
   add rdi, 8
-  mov [rdi], rcx                ; Insert length
+  mov [rdi], byte 0             ; Insert immediate flag
+
+  add rdi, 1
+  mov [rdi], byte cl            ; Insert length
 
   ;; Insert word string
   add rdi, 1
@@ -469,6 +533,30 @@ forth_asm CREATE, 'CREATE'
 
   next
 
+;; Mark the last added word as immediate.
+forth IMMEDIATE, 'IMMEDIATE', 1
+  dq LIT, 1
+  dq LATEST, GET
+  dq LIT, 8, PLUS
+  dq PUT_BYTE
+  dq EXIT
+
+;; Given the address of a word, return 0 if the given word is not immediate.
+forth IS_IMMEDIATE, 'IMMEDIATE?'
+  dq LIT, 8, PLUS
+  dq GET_BYTE
+  dq EXIT
+
+;; Enter immediate mode, immediately
+forth INTO_IMMEDIATE, '[', 1
+  dq LIT, 0, STATE, PUT_BYTE
+  dq EXIT
+
+;; Enter compilation mode
+forth OUTOF_IMMEDIATE, ']'
+  dq LIT, 1, STATE, PUT_BYTE
+  dq EXIT
+
 forth MAIN, 'MAIN'
   dq HELLO
   dq INTERPRET