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Calculate defword entry length with %strlen

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This commit is contained in:
Cesar Blum 2020-10-01 21:49:54 -07:00
parent d55d6bc190
commit e5b0b97643
1 changed files with 23 additions and 22 deletions
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45
sectorforth.asm
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@ -59,13 +59,14 @@ LENMASK equ 0x1f
%define link 0
; defword lays out a dictionary entry where it is expanded.
%macro defword 3-4 0 ; name, length, label, flags
word_%3:
%macro defword 2-3 0 ; name, label, flags
word_%2:
dw link ; link to previous word
%define link word_%3
db %4+%2 ; flags+length
%define link word_%2
%strlen %%len %1
db %3+%%len ; flags+length
db %1 ; name
%3: ; code starts here
%2: ; code starts here
%endmacro
; NEXT advances execution to the next word. The actual code is
@ -85,25 +86,25 @@ word_%3:
; nand ( x1 x2 -- n ) NAND the two values at the top of the stack
; exit ( r:addr -- ) Resume execution at address at the top of
; the return stack
defword "@",1,FETCH
defword "@",FETCH
pop bx
push word [bx]
NEXT
defword "!",1,STORE
defword "!",STORE
pop bx
pop word [bx]
NEXT
defword "sp@",3,SPFETCH
defword "sp@",SPFETCH
push sp
NEXT
defword "rp@",3,RPFETCH
defword "rp@",RPFETCH
push bp
NEXT
defword "0=",2,ZEROEQUALS
defword "0=",ZEROEQUALS
pop ax
test ax,ax
setnz al ; AL=0 if ZF=1, else AL=1
@ -112,14 +113,14 @@ word_%3:
push ax
NEXT
defword "+",1,PLUS
defword "+",PLUS
pop bx
pop ax
add ax,bx
push ax
NEXT
defword "nand",4,NAND
defword "nand",NAND
pop bx
pop ax
and ax,bx
@ -127,7 +128,7 @@ word_%3:
push ax
NEXT
defword "exit",4,EXIT
defword "exit",EXIT
xchg sp,bp ; swap SP and BP, SP controls return stack
pop si ; pop address to next word
xchg sp,bp ; restore SP and BP
@ -139,15 +140,15 @@ word_%3:
; TIB could be left out. But it is exposed so that sectorforth
; code that accesses the parse area can be written in an idiomatic
; fashion (e.g. TIB >IN @ +).
defword "tib",3,TIBVAR
defword "tib",TIBVAR
push word TIB
NEXT
defword "state",5,STATEVAR
defword "state",STATEVAR
push word STATE
NEXT
defword ">in",3,TOINVAR
defword ">in",TOINVAR
push word TOIN
NEXT
@ -158,12 +159,12 @@ next:
jmp ax ; jump directly to it
; Words and data space for the HERE and LATEST variables.
defword "here",4,HEREVAR
defword "here",HEREVAR
push word HERE
NEXT
HERE: dw start_HERE
defword "latest",6,LATESTVAR
defword "latest",LATESTVAR
push word LATEST
NEXT
LATEST: dw word_SEMICOLON ; initialized to last word in dictionary
@ -173,7 +174,7 @@ LATEST: dw word_SEMICOLON ; initialized to last word in dictionary
;
; KEY waits for a key press and pushes its scan code (AH) and
; ASCII character (AL) to the stack, both in a single cell.
defword "key",3,KEY
defword "key",KEY
mov ah,0
int 0x16
push ax
@ -181,7 +182,7 @@ LATEST: dw word_SEMICOLON ; initialized to last word in dictionary
; EMIT writes to the screen the ASCII character corresponding to
; the lowest 8 bits of the value at the top of the stack.
defword "emit",4,EMIT
defword "emit",EMIT
pop ax
call writechar
NEXT
@ -190,7 +191,7 @@ LATEST: dw word_SEMICOLON ; initialized to last word in dictionary
; creates a dictionary entry for it, writes machine code to jump
; to DOCOL, updates LATEST and HERE, and switches to compilation
; state.
defword ":",1,COLON
defword ":",COLON
call token ; parse word from input
push si
mov si,di ; set parsed word as string copy source
@ -240,7 +241,7 @@ DOCOL:
; of EXIT to the end of a new word definition, makes the word
; visible in the dictionary, and switches back to interpretation
; state.
defword ";",1,SEMICOLON,F_IMMEDIATE
defword ";",SEMICOLON,F_IMMEDIATE
mov bx,[LATEST]
and byte [bx+2],~F_HIDDEN ; reveal new word
mov byte [STATE],0 ; switch to interpretation state