megadrive_test1: src/libc/stdlib.c annotate

megadrive_test1

expanding the megadrive code

author	John Tsiombikas <nuclear@member.fsf.org>
date	Sat, 11 Feb 2017 08:56:42 +0200
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rev	line source
nuclear@6	1 #include <stdlib.h>
nuclear@6	2 #include <ctype.h>
nuclear@6	3
nuclear@6	4 int atoi(const char *str)
nuclear@6	5 {
nuclear@6	6 return strtol(str, 0, 10);
nuclear@6	7 }
nuclear@6	8
nuclear@6	9 long atol(const char *str)
nuclear@6	10 {
nuclear@6	11 return strtol(str, 0, 10);
nuclear@6	12 }
nuclear@6	13
nuclear@6	14 long strtol(const char str, char *endp, int base)
nuclear@6	15 {
nuclear@6	16 long acc = 0;
nuclear@6	17 int sign = 1;
nuclear@6	18
nuclear@6	19 while(isspace(*str)) str++;
nuclear@6	20
nuclear@6	21 if(base == 0) {
nuclear@6	22 if(str[0] == '0') {
nuclear@6	23 if(str[1] == 'x' \|\| str[1] == 'X') {
nuclear@6	24 base = 16;
nuclear@6	25 } else {
nuclear@6	26 base = 8;
nuclear@6	27 }
nuclear@6	28 } else {
nuclear@6	29 base = 10;
nuclear@6	30 }
nuclear@6	31 }
nuclear@6	32
nuclear@6	33 if(*str == '+') {
nuclear@6	34 str++;
nuclear@6	35 } else if(*str == '-') {
nuclear@6	36 sign = -1;
nuclear@6	37 str++;
nuclear@6	38 }
nuclear@6	39
nuclear@6	40 while(*str) {
nuclear@6	41 long val;
nuclear@6	42 char c = tolower(*str);
nuclear@6	43
nuclear@6	44 if(isdigit(c)) {
nuclear@6	45 val = *str - '0';
nuclear@6	46 } else if(c >= 'a' \|\| c <= 'f') {
nuclear@6	47 val = 10 + c - 'a';
nuclear@6	48 }
nuclear@6	49 if(val >= base) {
nuclear@6	50 break;
nuclear@6	51 }
nuclear@6	52
nuclear@6	53 acc = acc * base + val;
nuclear@6	54 str++;
nuclear@6	55 }
nuclear@6	56
nuclear@6	57 if(endp) {
nuclear@6	58 endp = (char)str;
nuclear@6	59 }
nuclear@6	60
nuclear@6	61 return sign > 0 ? acc : -acc;
nuclear@6	62 }