X-Git-Url: https://git.rrq.au/?a=blobdiff_plain;f=main.asm;h=c9a7fc42acc1d9deb022010648f9c36c1aab30ee;hb=fbd07fa0c1aaad0cca46f9b1fc4839e053454f03;hp=ae3f9913eae15ea9f26a86c1b3d04a05215e2a8c;hpb=055f2efc3011a2102125cd0001adcff1cc6feab9;p=rrq%2Fjonasforth.git diff --git a/main.asm b/main.asm index ae3f991..c9a7fc4 100644 --- a/main.asm +++ b/main.asm @@ -87,18 +87,12 @@ macro forth_asm label, name, immediate { .start: } -;; Define a Forth word that is implemented in Forth. (The body will be a list of -;; 'dq' statements.) -macro forth label, name, immediate { - header label, name, immediate - dq DOCOL -} - segment readable executable entry main -include "impl.asm" +include "impl.asm" ; Misc. subroutines +include "bootstrap.asm" ; Forth words encoded in Assembly main: cld ; Clear direction flag so LODSQ does the right thing. @@ -201,18 +195,6 @@ forth_asm EMIT, 'EMIT' popr rsi next -;; Prints a newline to standard output. -forth NEWLINE, 'NEWLINE' - dq LIT, $A - dq EMIT - dq EXIT - -;; Prints a space to standard output. -forth SPACE, 'SPACE' - dq LIT, ' ' - dq EMIT - dq EXIT - ;; Read a word from standard input and push it onto the stack as a pointer and a ;; size. The pointer is valid until the next call to READ_WORD. forth_asm READ_WORD, 'READ-WORD' @@ -225,6 +207,25 @@ forth_asm READ_WORD, 'READ-WORD' mov rsi, [.rsi] next +;; Read a word from a buffer. Expects (buffer buffer-length) on the stack. +;; Updates buffer and buffer-length, such that the word has been removed from +;; the buffer. Appends (word-buffer word-buffer-length) to the stack. +forth_asm POP_WORD, 'POP-WORD' + pushr rsi + + pop rcx ; Length + pop rsi ; Buffer + + call pop_word + + push rsi ; Updated buffer + push rcx ; Length of updated buffer + push rdi ; Word buffer + push rdx ; Length of word buffer + + popr rsi + next + ;; Takes a string on the stack and replaces it with the decimal number that the ;; string represents. forth_asm PARSE_NUMBER, 'PARSE-NUMBER' @@ -238,11 +239,6 @@ forth_asm PARSE_NUMBER, 'PARSE-NUMBER' push rax ; Result next -forth READ_NUMBER, 'READ-NUMBER' - dq READ_WORD - dq PARSE_NUMBER - dq EXIT - ;; Takes a string (in the form of a pointer and a length on the stack) and ;; prints it to standard output. forth_asm TELL, 'TELL' @@ -297,55 +293,6 @@ forth_asm NOT_, 'NOT' 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. -forth INTERPRET, 'INTERPRET' - ;; Read word - dq READ_WORD - dq PAIRDUP - ;; Stack is (word length word length). - dq FIND ; Try to find word - dq DUP_ - dq ZBRANCH, 8 * 22 ; Check if word is found - - ;; - Word is found - - - dq STATE, GET, ZBRANCH, 8 * 11 ; Check whether we are in compilation or immediate mode - - ;; (Word found, compilation mode) - dq DUP_, IS_IMMEDIATE, NOT_, ZBRANCH, 8 * 6 ; If the word is immediate, continue as we would in immediate mode - - ;; Otherwise, we want to compile this word - dq TCFA - dq COMMA - dq DROP, DROP - dq EXIT - - ;; (Word found, immediate mode) - ;; Execute word - dq TCFA - ;; Stack is (word length addr) - dq SWAP, DROP - dq SWAP, DROP - ;; Stack is (addr) - dq EXEC - dq EXIT - - ;; - 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. forth_asm DOTU, '.U' mov [.length], 0 @@ -459,31 +406,6 @@ forth_asm TIMESMOD, '/MOD' push rdx ; a % b next -;; Get the location of the STATE variable. It can be set with '!' and read with -;; '@'. -forth STATE, 'STATE' - dq LIT, var_STATE - dq EXIT - -;; Get the location of the LATEST variable. It can be set with '!' and read with -;; '@'. -forth LATEST, 'LATEST' - dq LIT, latest_entry - dq EXIT - -;; Get the location at which compiled words are expected to be added. This -;; pointer is usually modified automatically when calling ',', but we can also -;; read it manually with 'HERE'. -forth HERE, 'HERE' - dq LIT, here - dq EXIT - -forth COMMA, ',' - dq HERE, GET, PUT ; Set the memory at the address pointed to by HERE - dq HERE, GET, LIT, 8, PLUS ; Calculate new address for HERE to point to - dq HERE, PUT ; Update HERE to point to the new address - dq EXIT - ;; Read user input until next " character is found. Push a string containing the ;; input on the stack as (buffer length). Note that the buffer is only valid ;; until the next call to S" and that no more than 255 character can be read. @@ -550,30 +472,6 @@ 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_asm TICK, "'" lodsq push rax @@ -612,6 +510,25 @@ forth MAIN, 'MAIN' dq BRANCH, -8 * 2 dq TERMINATE +;; Built-in variables: + +forth STATE, 'STATE' + dq LIT, var_STATE + dq EXIT + +forth LATEST, 'LATEST' + dq LIT, latest_entry + dq EXIT + +forth HERE, 'HERE' + dq LIT, here + dq EXIT + +forth SYSCODE, 'SYSCODE' + dq LIT, sysf + dq LIT, sysf.len + dq EXIT + segment readable writable ;; The LATEST variable holds a pointer to the word that was last added to the @@ -645,3 +562,12 @@ here_top rq $4000 ;; Return stack rq $2000 return_stack_top: + +segment readable + +;; We store some Forth code in sys.f that defined common words that the user +;; would expect to have available at startup. To execute these words, we just +;; include the file directly in the binary, and then interpret it at startup. +sysf file 'sys.f' +sysf.len = $ - sysf +