[U-Boot] [RFC PATCH] SPL: replace ctype implementation with tiny version

[Andrew F. Davis]

On 01/20/2017 04:33 PM, Andre Przywara wrote:
> The ctype implementation (isdigit() & friends) works with an array of
> 256 Bytes - one for each character. This is pretty big in SPL terms,
> so let's replace this "bloated" implementation with a tiny version
> using C statements. This only implements the functions that the SPL
> requires and confines this change only to an actual SPL build.
> Saves about 200 Bytes from the SPL code size.
> 

Saves us a very needed 256 bytes on AM335x!

Acked-by: Andrew F. Davis <afd at ti.com>

Thanks,
Andrew

> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
> ---
> Hi,
> 
> some people voiced concerns about running out of SPL code space when
> adding new features. In this particular case this was an issue when
> looking at the SPL FIT extension series[1].
> This patch here on top of this series saves more space than the SPL FIT
> series consumed, so I trade this as a bait to people wrestling with this
> problem ;-)
> 
> Cheers,
> Andre.
> 
> [1] http://lists.denx.de/pipermail/u-boot/2017-January/278772.html
> 
>  include/linux/tiny_ctype.h | 12 ++++++++++++
>  lib/Makefile               |  2 ++
>  lib/strto.c                |  4 ++++
>  3 files changed, 18 insertions(+)
>  create mode 100644 include/linux/tiny_ctype.h
> 
> diff --git a/include/linux/tiny_ctype.h b/include/linux/tiny_ctype.h
> new file mode 100644
> index 0000000..4910412
> --- /dev/null
> +++ b/include/linux/tiny_ctype.h
> @@ -0,0 +1,12 @@
> +#ifndef _LINUX_CTYPE_H
> +#define _LINUX_CTYPE_H
> +
> +#define isdigit(c)	(((c) >= '0') && ((c) <= '9'))
> +#define isxdigit(c)	(isdigit(c) || \
> +			 ((c) >= 'A' && (c) <= 'F') || \
> +			 ((c) >= 'a' && (c) <= 'f'))
> +#define islower(c)	((((c) >= 'a') && ((c) <= 'z')) || ((c) >= 223))
> +
> +#define toupper(c)	((((c) >= 'a') && ((c) <= 'z')) ? (c) - 32 : (c))
> +
> +#endif
> diff --git a/lib/Makefile b/lib/Makefile
> index 23e9f1e..15385fd 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -66,7 +66,9 @@ obj-y += display_options.o
>  CFLAGS_display_options.o := $(if $(BUILD_TAG),-DBUILD_TAG='"$(BUILD_TAG)"')
>  obj-$(CONFIG_BCH) += bch.o
>  obj-y += crc32.o
> +ifndef CONFIG_SPL_BUILD
>  obj-y += ctype.o
> +endif
>  obj-y += div64.o
>  obj-y += hang.o
>  obj-y += linux_compat.o
> diff --git a/lib/strto.c b/lib/strto.c
> index e93a4f5..9e9ba75 100644
> --- a/lib/strto.c
> +++ b/lib/strto.c
> @@ -11,7 +11,11 @@
>  
>  #include <common.h>
>  #include <errno.h>
> +#ifdef CONFIG_SPL_BUILD
> +#include <linux/tiny_ctype.h>
> +#else
>  #include <linux/ctype.h>
> +#endif
>  
>  unsigned long simple_strtoul(const char *cp, char **endp,
>  				unsigned int base)
>