From fa97bdf92709adaaf8b9a5164a895e262a4fcf60 Mon Sep 17 00:00:00 2001 From: Pekka Enberg Date: Sun, 11 Jul 2010 11:06:57 +0300 Subject: x86, setup: Early-boot serial I/O support This patch adds serial I/O support to the real-mode setup (very early boot) printf(). It's useful for debugging boot code when running Linux under KVM, for example. The actual code was lifted from early printk. Cc: Cyrill Gorcunov Cc: Ingo Molnar Cc: Yinghai Lu Signed-off-by: Pekka Enberg LKML-Reference: <1278835617-11368-1-git-send-email-penberg@cs.helsinki.fi> Signed-off-by: H. Peter Anvin --- arch/x86/boot/string.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) (limited to 'arch/x86/boot/string.c') diff --git a/arch/x86/boot/string.c b/arch/x86/boot/string.c index f94b7a0c2ab..aba29df4a7b 100644 --- a/arch/x86/boot/string.c +++ b/arch/x86/boot/string.c @@ -30,6 +30,22 @@ int strcmp(const char *str1, const char *str2) return 0; } +int strncmp(const char *cs, const char *ct, size_t count) +{ + unsigned char c1, c2; + + while (count) { + c1 = *cs++; + c2 = *ct++; + if (c1 != c2) + return c1 < c2 ? -1 : 1; + if (!c1) + break; + count--; + } + return 0; +} + size_t strnlen(const char *s, size_t maxlen) { const char *es = s; @@ -48,3 +64,28 @@ unsigned int atou(const char *s) i = i * 10 + (*s++ - '0'); return i; } + +/* Works only for digits and letters, but small and fast */ +#define TOLOWER(x) ((x) | 0x20) + +unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base) +{ + unsigned long long result = 0; + + if (base == 16 && cp[0] == '0' && TOLOWER(cp[1]) == 'x') + cp += 2; + + while (isxdigit(*cp)) { + unsigned int value; + + value = isdigit(*cp) ? *cp - '0' : TOLOWER(*cp) - 'a' + 10; + if (value >= base) + break; + result = result * base + value; + cp++; + } + if (endp) + *endp = (char *)cp; + + return result; +} -- cgit v1.2.3-70-g09d2