From: Jonas Hvid Date: Tue, 10 Dec 2019 14:51:24 +0000 (+0100) Subject: Add error handling to parse_number X-Git-Url: https://git.rrq.au/?a=commitdiff_plain;h=24d3a4952e2e2b6db7a64eb2a8caffd2976a02ee;p=rrq%2Fjonasforth.git Add error handling to parse_number --- diff --git a/impl.asm b/impl.asm index bb796ab..9ad2278 100644 --- a/impl.asm +++ b/impl.asm @@ -1,5 +1,39 @@ segment readable executable +macro printlen msg, len { + push rsi + add rsp, 8 + + mov rsi, msg + mov rdx, len + mov rax, 1 + mov rdi, 1 + syscall + + sub rsp, 8 + pop rsi +} + +macro newline { + push $A + printlen rsp, 1 +} + +macro print msg { + printlen msg, msg#.len +} + +macro exit code { + mov rax, $3C + mov rdi, code + syscall +} + +struc string bytes { + . db bytes + .len = $ - . +} + ;; Find the given word in the dictionary of words. If no such word exists, ;; return 0. ;; @@ -125,12 +159,15 @@ parse_number: ;; Now, rax = 10^(rcx - 1). ;; We need to calulate the value of the character at rdi[length - rcx]. - mov rbx, rdi + mov rbx, rdi add rbx, [.length] sub rbx, rcx movzx rbx, byte [rbx] sub rbx, '0' + cmp rbx, 10 + jae .error + ;; Multiply this value by rax to get (10^(rcx-1) * parse_char(rdi[length - rcx])), ;; then add this to the result. mul rbx @@ -144,6 +181,13 @@ parse_number: mov rax, r8 ret +.error: + push rdi + print parse_number.error_msg + pop rdi + printlen rdi, [.length] + newline + exit 100 segment readable writable @@ -156,4 +200,5 @@ read_word.length db ? read_word.char_buffer db ? parse_number.length dq ? +parse_number.error_msg string "Invalid number: "