dq docol
}
+
+
segment readable executable
+entry main
+
+include "impl.asm"
+
main:
cld ; Clear direction flag so LODSQ does the right thing.
mov rbp, return_stack_top ; Initialize return stack
;; dictionary entry for that word. If no such word exists, return 0.
forth_asm FIND, 'FIND'
mov [.rsi], rsi
- pop [.search_length]
- pop [.search_buffer]
- ;; RSI contains the entry we are currently looking at
+ pop [find.search_length]
+ pop [find.search_buffer]
mov rsi, [latest_entry] ; Start with the last added word
+ call find
+ push rsi
-.loop:
- movzx rcx, byte [rsi + 8] ; Length of word being looked at
- cmp rcx, [.search_length]
- jne .next ; If the words don't have the same length, we have the wrong word
-
- ;; Otherwise, we need to compare strings
- lea rdx, [rsi + 8 + 1] ; Location of character being compared in entry
- mov rdi, [.search_buffer] ; Location of character being compared in search buffer
-.compare_char:
- mov al, [rdx]
- mov ah, [rdi]
- cmp al, ah
- jne .next ; They don't match; try again
- inc rdx ; These characters match; look at the next ones
- inc rdi
- loop .compare_char
-
- jmp .found ; They match! We are done.
-
-.next:
- mov rsi, [rsi] ; Look at the previous entry
- cmp rsi, 0
- jnz .loop ; If there is no previous word, exit and return 0
-
-.found:
+ mov rsi, [.rsi]
+ next
push rsi
mov rsi, [.rsi]
;; size. The pointer is valid until the next call to READ_WORD.
forth_asm READ_WORD, 'READ-WORD'
mov [.rsi], rsi
- mov [.rax], rax
-.skip_whitespace:
- ;; Read characters into .char_buffer until one of them is not whitespace.
- mov rax, 0
- mov rdi, 0
- mov rsi, .char_buffer
- mov rdx, 1
- syscall
-
- cmp [.char_buffer], ' '
- je .skip_whitespace
- cmp [.char_buffer], $A
- je .skip_whitespace
-
-.alpha:
- ;; We got a character that wasn't whitespace. Now read the actual word.
- mov [.length], 0
-
-.read_alpha:
- mov al, [.char_buffer]
- movzx rbx, [.length]
- mov rsi, .buffer
- add rsi, rbx
- mov [rsi], al
- inc [.length]
-
- mov rax, 0
- mov rdi, 0
- mov rsi, .char_buffer
- mov rdx, 1
- syscall
-
- cmp [.char_buffer], ' '
- je .end
- cmp [.char_buffer], $A
- jne .read_alpha
-
-.end:
- push .buffer
- movzx rax, [.length]
- push rax
+ call read_word
+ push rdi ; Buffer
+ push rdx ; Length
mov rsi, [.rsi]
- mov rax, [.rax]
-
next
;; Takes a string on the stack and replaces it with the decimal number that the
;; string represents.
forth_asm PARSE_NUMBER, 'PARSE-NUMBER'
- pop [.length] ; Length
- pop rdi ; String pointer
- mov r8, 0 ; Result
-
- ;; Add (10^(rcx-1) * parse_char(rdi[length - rcx])) to the accumulated value
- ;; for each rcx.
- mov rcx, [.length]
-.loop:
- ;; First, calcuate 10^(rcx - 1)
- mov rax, 1
+ pop [parse_number.length] ; Length
+ pop [parse_number.buffer] ; String pointer
- mov r9, rcx
- .exp_loop:
- dec r9
- jz .break
- mov rbx, 10
- mul rbx
- jmp .exp_loop
- .break:
-
- ;; Now, rax = 10^(rcx - 1).
-
- ;; We need to calulate the value of the character at rdi[length - rcx].
- mov rbx, rdi
- add rbx, [.length]
- sub rbx, rcx
- movzx rbx, byte [rbx]
- sub rbx, '0'
-
- ;; Multiply this value by rax to get (10^(rcx-1) * parse_char(rdi[length - rcx])),
- ;; then add this to the result.
- mul rbx
-
- ;; Add that value to r8
- add r8, rax
-
- dec rcx
- jnz .loop
-
- push r8
+ push rsi
+ call parse_number
+ pop rsi
+ push rax ; Result
next
forth READ_NUMBER, 'READ-NUMBER'
latest_entry dq initial_latest_entry
-FIND.search_length dq ?
-FIND.search_buffer dq ?
FIND.rsi dq ?
READ_WORD.rsi dq ?
-READ_WORD.rax dq ?
-READ_WORD.max_size = $FF
-READ_WORD.buffer rb READ_WORD.max_size
-READ_WORD.length db ?
-READ_WORD.char_buffer db ?
+READ_WORD.rbp dq ?
DOTU.chars db '0123456789ABCDEF'
DOTU.buffer rq 16 ; 64-bit number has no more than 16 digits in hex
DOTU.length dq ?
DOTU.printed_length dq ?
-PARSE_NUMBER.length dq ?
-
;; Return stack
rq $2000
return_stack_top:
projects / rrq / jonasforth.git / blobdiff