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9e467388de
The existing first-order LCG (seed = 470001 * seed % 999563) has several quality problems: - Output range limited to [1, 999562] (~20 bits) instead of full 32-bit - Lower bits have very short periods (8-bit period = 1, 16-bit = 105) - Overall period only ~1M, far too short for many applications - Causes mbedtls_rsa_gen_key to loop forever when rand() consumption aligns with the cycle length (issue #16760) Replace the entire order-based LCG implementation (CONFIG_LIBC_RAND_ORDER 0-3) with Marsaglia's xorshift32: - Full 32-bit output range - Period 2^32 - 1 (~4.29 billion) - Fast: just three XOR/shift operations - No floating-point math needed - No CONFIG_LIBC_RAND_ORDER configuration required Remove the CONFIG_LIBC_RAND_ORDER Kconfig option and clean up all defconfig references (12 boards) and related comments. Signed-off-by: hanzhijian <hanzhijian@zepp.com>
50 lines
1.6 KiB
Text
50 lines
1.6 KiB
Text
#
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# For a description of the syntax of this configuration file,
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# see the file kconfig-language.txt in the NuttX tools repository.
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#
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menu "stdlib Options"
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config LIBC_HOMEDIR
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string "Home directory"
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default "/"
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---help---
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The home directory to use with operations like such as 'cd ~'
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config LIBC_TMPDIR
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string "Temporary file directory"
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default "/tmp"
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---help---
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If a write-able file system is selected, this string will be
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provided to specify the full path to a directory where temporary
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files can be created. This would be a good application of RAM disk:
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To provide temporary storage for application data.
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config LIBC_MAX_TMPFILE
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int "Maximum size of a temporary file path"
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default 32
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---help---
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If a write-able file system is selected, then temporary file may be
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supported at the path provided by LIBC_TMPDIR. The tmpnam() interface
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keeps a static copy of this last filename produced; this value is the
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maximum size of that last filename. This size is the size of the full
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file path.
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config LIBC_MAX_EXITFUNS
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int "Maximum amount of exit functions"
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default 0
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---help---
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Configure the amount of exit functions for atexit/on_exit. The ANSI
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default is 32, but most likely we don't need as many.
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config LIBC_DISABLE_HEXSTR_TO_FLOAT
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bool "Disable hex-string to float/double conversions"
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default DEFAULT_SMALL
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---help---
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Disables parsing of hexadecimal floating-point constants (C99 %a),
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e.g., "0x1.fp3", in strtod(), strtof(), strtold(), and sscanf("%a").
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This saves flash space since hex-float parsing adds significant code
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and is rarely needed in embedded systems. Decimal float parsing remains
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available.
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endmenu # stdlib Options
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