• From: TinyC for the SD-8516

For actual built ins I mainly have putchar() and getchar() which use the BASIC IO_ library at INT $05. After that, a lot can be written in C.

• Builtin: putchar()
• Builtin: getchar()

int print(char *s) {
    int i = 0;
    while (s[i] != 0) {
        putchar(s[i]);
        i = i + 1;
    }
    return 0;
}

int println(char *s) {
    print(s);
    putchar(13);
    putchar(10);
    return 0;
}

int printnum(int n) {
    char *buf = 0xDF00;
    int i = 0;
    int neg = 0;
    if (n < 0) {
        neg = 1;
        n = 0 - n;
    }
    if (n == 0) {
        putchar('0');
        return 0;
    }
    while (n > 0) {
        *(buf + i) = n - (n / 10) * 10 + '0';
        n = n / 10;
        i = i + 1;
    }
    if (neg) {
        putchar('-');
    }
    while (i > 0) {
        i = i - 1;
        putchar(buf[i]);
    }
    return 0;
}

int readline(char *buf, int max) {
    int i = 0;
    int c = 0;
    while (i < max - 1) {
        c = getchar();
        if (c == 13) {
            putchar(13);
            putchar(10);
            *(buf + i) = 0;
            return i;
        }
        if (c == 8) {
            if (i > 0) {
                i = i - 1;
                putchar(8);
                putchar(' ');
                putchar(8);
            }
        } else {
            *(buf + i) = c;
            putchar(c);
            i = i + 1;
        }
    }
    *(buf + i) = 0;
    return i;
}

int strcmp(char *a, char *b) {
    int i = 0;
    while (a[i] != 0) {
        if (a[i] != b[i]) {
            return a[i] - b[i];
        }
        i = i + 1;
    }
    return a[i] - b[i];
}

int strlen(char *s) {
    int i = 0;
    while (s[i] != 0) {
        i = i + 1;
    }
    return i;
}

int strcpy(char *dst, char *src) {
    int i = 0;
    while (src[i] != 0) {
        *(dst + i) = src[i];
        i = i + 1;
    }
    *(dst + i) = 0;
    return i;
}

int strcat(char *dst, char *src) {
    int di = strlen(dst);
    int si = 0;
    while (src[si] != 0) {
        *(dst + di) = src[si];
        di = di + 1;
        si = si + 1;
    }
    *(dst + di) = 0;
    return di;
}

int strncmp(char *a, char *b, int n) {
    int i = 0;
    while (i < n) {
        if (a[i] != b[i]) {
            return a[i] - b[i];
        }
        if (a[i] == 0) { return 0; }
        i = i + 1;
    }
    return 0;
}

int strchr(char *s, int c) {
    int i = 0;
    while (s[i] != 0) {
        if (s[i] == c) { return i; }
        i = i + 1;
    }
    return 0 - 1;
}

int atoi(char *s) {
    int n = 0;
    int i = 0;
    while (isdigit(s[i])) {
        n = n * 10 + s[i] - '0';
        i = i + 1;
    }
    return n;
}

int itoa(int n, char *buf) {
    int i = 0;
    int neg = 0;
    if (n < 0) {
        neg = 1;
        n = 0 - n;
    }
    if (n == 0) {
        *(buf) = '0';
        *(buf + 1) = 0;
        return 1;
    }
    char *tmp = 0xDEF0;
    while (n > 0) {
        *(tmp + i) = n - (n / 10) * 10 + '0';
        n = n / 10;
        i = i + 1;
    }
    int j = 0;
    if (neg) {
        *(buf) = '-';
        j = 1;
    }
    while (i > 0) {
        i = i - 1;
        *(buf + j) = tmp[i];
        j = j + 1;
    }
    *(buf + j) = 0;
    return j;
}

int memset(char *p, int val, int len) {
    int i = 0;
    while (i < len) {
        *(p + i) = val;
        i = i + 1;
    }
    return 0;
}

int memcpy(char *dst, char *src, int len) {
    int i = 0;
    while (i < len) {
        *(dst + i) = src[i];
        i = i + 1;
    }
    return 0;
}

int isdigit(int c) {
    if (c >= '0') {
        if (c <= '9') {
            return 1;
        }
    }
    return 0;
}

int isalpha(int c) {
    if (c >= 'a') {
        if (c <= 'z') {
            return 1;
        }
    }
    if (c >= 'A') {
        if (c <= 'Z') {
            return 1;
        }
    }
    return 0;
}

int isspace(int c) {
    if (c == ' ') { return 1; }
    if (c == 9) { return 1; }
    if (c == 10) { return 1; }
    if (c == 13) { return 1; }
    return 0;
}

int isupper(int c) {
    if (c >= 'A') {
        if (c <= 'Z') {
            return 1;
        }
    }
    return 0;
}

int islower(int c) {
    if (c >= 'a') {
        if (c <= 'z') {
            return 1;
        }
    }
    return 0;
}

int toupper(int c) {
    if (islower(c)) {
        return c - 32;
    }
    return c;
}

int tolower(int c) {
    if (isupper(c)) {
        return c + 32;
    }
    return c;
}

int abs(int n) {
    if (n < 0) { return 0 - n; }
    return n;
}

int min(int a, int b) {
    if (a < b) { return a; }
    return b;
}

int max(int a, int b) {
    if (a > b) { return a; }
    return b;
}