diff options
Diffstat (limited to 'twasm/asm/main.asm')
| -rw-r--r-- | twasm/asm/main.asm | 48 |
1 files changed, 25 insertions, 23 deletions
diff --git a/twasm/asm/main.asm b/twasm/asm/main.asm index 5ebc9cb..69708bc 100644 --- a/twasm/asm/main.asm +++ b/twasm/asm/main.asm @@ -650,7 +650,7 @@ tokenise: .loop: cmp rdi, rsi ; if current byte greater than last byte - jge .break ; then break + jge .break ; then break mov dl, [rdi] ; dl = current byte @@ -667,18 +667,17 @@ tokenise: push rdi push rax push rdx - ; TODO probably should not ignore null bytes - mov rsi, whitespace_2 ; rsi -> list of whitespace (ignored) bytes - mov rdi, 2 ; rdi = size of list in bytes + mov rsi, whitespace_2 ; rsi -> list of whitespace bytes + mov rdi, 2 ; rdi = size of the list in bytes ; dl = current byte call elemb ; al = 0 if not whitespace, 1 if whitespace - cmp al, 1 ; check if current byte is whitespace - pop rdx - pop rax - pop rdi - pop rsi - je .skip_byte_whitespace + test eax, 1 ; check if current byte is whitespace + pop rdx ; dl = current byte + pop rax ; rax = number of tokens processed + pop rdi ; rdi -> current byte of program + pop rsi ; rsi -> last byte of program + jnz .skip_byte_whitespace test byte [.expecting], E_OPERATOR ; check if an operator is expected jnz .operator ; if so, handle it @@ -690,17 +689,19 @@ tokenise: call print.debug mov rsi, .msg_comment call print - pop rsi + pop rsi ; rsi -> last byte of program + test byte [.expecting], E_COMMENT ; make sure a comment is expected jz .unexpected_comment ; if not, error .comment_loop: - ; TODO range check rdi mov dl, [rdi] ; dl = current byte cmp dl, 0x0A ; if current byte is a newline je .comment_break ; then break inc rdi ; point to next unread byte + cmp rdi, rsi + jge .break jmp .comment_loop .comment_break: jmp .loop @@ -729,7 +730,7 @@ tokenise: test byte [.expecting], E_COMMA ; make sure a comma was expected jz .unexpected_comma ; if not, error inc rdi - mov [.expecting], E_WHITESPACE | E_OPERAND ; else, make operand expected + mov byte [.expecting], E_WHITESPACE | E_OPERAND ; else, make operand expected jmp .loop ; and loop .newline_mk_flags: @@ -757,15 +758,12 @@ tokenise: call print pop rsi - push rax + mov rcx, rax ; rcx = number of tokens processed xor eax, eax ; eax = number of bytes in operator mov [.pending_operator], eax ; zero pending operator .operator_loop: ; TODO give this its own error - ; TODO make this pop rax - cmp eax, 4 ; check that operator is short enough - jg .unexpected_operator ; if not, error mov dl, [rdi] ; next byte @@ -781,8 +779,12 @@ tokenise: mov [.pending_operator + eax], dl - inc rax ; inc byte counter + inc eax ; inc byte counter inc rdi ; inc byte pointer + cmp eax, 4 ; check that operator is short enough + jg .unexpected_operator ; if not, error + cmp rdi, rsi + jge .break jmp .operator_loop ; and loop .operator_break: @@ -791,11 +793,11 @@ tokenise: mov edi, [.pending_operator] ; edi = operator to be searched call identify_operator - ; ax = operator's token ID - mov cx, ax ; cx = operator's token ID for safe keeping - - pop rdi ; rdi = byte counter - pop rax ; rax = tokens processed + ; ax = operator's token ID + push rcx + mov ecx, eax ; cx = operator's token ID + pop rax ; rax = tokens processed + pop rdi ; rdi = byte counter mov [TOKEN_TABLE_ADDR + rax * 2], cx inc rax ; plus 1 token processed |