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(libretro-common) features_cpu - reimplement ARM cpu features code
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twinaphex
parent
af39105c04
commit
f20b969165
@ -287,100 +287,76 @@ static void arm_enable_runfast_mode(void)
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#endif
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#if defined(__linux__) && !defined(CPU_X86)
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/* Extract the content of a the first occurrence of a given field in
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* the content of /proc/cpuinfo and return it as a heap-allocated
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* string that must be freed by the caller.
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*
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* Return NULL if not found
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*/
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static char *extract_cpuinfo_field(char* buffer,
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ssize_t length, const char* field)
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static unsigned char check_arm_cpu_feature(const char* feature)
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{
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int len;
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const char *q;
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int fieldlen = strlen(field);
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char* bufend = buffer + length;
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char* result = NULL;
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/* Look for first field occurrence,
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* and ensures it starts the line. */
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const char *p = buffer;
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unsigned char status = 0;
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FILE *fp = fopen("/proc/cpuinfo", "r");
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for (;;)
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if (fp)
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{
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p = memmem(p, bufend-p, field, fieldlen);
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if (p == NULL)
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return result;
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char line[1024];
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while (fgets(line , sizeof(line) , fp) != NULL)
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{
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if (strncmp(line, "Features\t: ", 11))
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continue;
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if (strstr(line + 11, feature) != NULL)
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status = 1;
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if (p == buffer || p[-1] == '\n')
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break;
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}
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p += fieldlen;
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fclose(fp);
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}
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/* Skip to the first column followed by a space */
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p += fieldlen;
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p = memchr(p, ':', bufend-p);
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if (p == NULL || p[1] != ' ')
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return result;
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/* Find the end of the line */
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p += 2;
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q = memchr(p, '\n', bufend-p);
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if (q == NULL)
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q = bufend;
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/* Copy the line into a heap-allocated buffer */
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len = q-p;
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result = malloc(len+1);
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if (result == NULL)
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return result;
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memcpy(result, p, len);
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result[len] = '\0';
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return result;
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return status;
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}
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/* Checks that a space-separated list of items
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* contains one given 'item'.
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* Returns 1 if found, 0 otherwise.
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*/
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static int has_list_item(const char* list, const char* item)
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static unsigned char get_arm_cpu_implementer(void)
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{
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const char* p = list;
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int itemlen = strlen(item);
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unsigned char implementer = 0;
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FILE *fp = fopen("/proc/cpuinfo", "r");
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if (list == NULL)
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return 0;
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if (fp)
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{
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char line[1024];
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while (*p)
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{
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const char* q;
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while (fgets(line , sizeof(line) , fp) != NULL)
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{
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if (strncmp(line, "CPU implementer\t: ", 18))
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continue;
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/* skip spaces */
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while (*p == ' ' || *p == '\t')
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p++;
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sscanf(line+18, "0x%02hhx", &implementer);
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/* find end of current list item */
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q = p;
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while (*q && *q != ' ' && *q != '\t')
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q++;
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if (itemlen == q-p && !memcmp(p, item, itemlen))
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return 1;
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/* skip to next item */
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p = q;
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}
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return 0;
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break;
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}
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fclose(fp);
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}
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return implementer;
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}
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typedef struct
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static unsigned short get_arm_cpu_part(void)
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{
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uint32_t mask;
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} CpuList;
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unsigned short part = 0;
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FILE *fp = fopen("/proc/cpuinfo", "r");
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if (fp)
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{
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char line[1024];
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while (fgets(line , sizeof(line) , fp) != NULL)
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{
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if (strncmp(line, "CPU part\t: ", 11))
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continue;
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sscanf(line+11, "0x%03hx", &part);
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break;
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}
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fclose(fp);
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}
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return part;
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}
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#if !defined(_SC_NPROCESSORS_ONLN)
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/* Parse an decimal integer starting from 'input', but not going further
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@ -734,118 +710,7 @@ uint64_t cpu_features_get(void)
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cpu |= RETRO_SIMD_MMXEXT;
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}
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#elif defined(__linux__)
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static bool cpu_inited_once = false;
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static uint64_t g_cpuFeatures = 0;
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enum
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{
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CPU_ARM_FEATURE_ARMv7 = (1 << 0),
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CPU_ARM_FEATURE_VFPv3 = (1 << 1),
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CPU_ARM_FEATURE_NEON = (1 << 2),
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CPU_ARM_FEATURE_LDREX_STREX = (1 << 3)
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};
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if (!cpu_inited_once)
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{
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ssize_t length;
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void *buf = NULL;
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if (filestream_read_file("/proc/cpuinfo", &buf, &length) == 1)
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{
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char* cpu_features = NULL;
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/* Extract architecture from the "CPU Architecture" field.
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* The list is well-known, unlike the the output of
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* the 'Processor' field which can vary greatly.
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*
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* See the definition of the 'proc_arch' array in
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* $KERNEL/arch/arm/kernel/setup.c and the 'c_show' function in
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* same file.
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*/
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char* cpu_arch = extract_cpuinfo_field(buf, length, "CPU architecture");
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if (cpu_arch)
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{
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char* end = NULL;
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int has_armv7 = 0;
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/* Read the initial decimal number, ignore the rest */
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long arch_number = strtol(cpu_arch, &end, 10);
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/* Here we assume that ARMv8 will be upwards compatible with v7
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* in the future. Unfortunately, there is no 'Features' field to
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* indicate that Thumb-2 is supported.
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*/
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if (end > cpu_arch && arch_number >= 7)
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has_armv7 = 1;
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/* Unfortunately, it seems that certain ARMv6-based CPUs
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* report an incorrect architecture number of 7!
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*
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* See http://code.google.com/p/android/issues/detail?id=10812
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*
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* We try to correct this by looking at the 'elf_format'
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* field reported by the 'Processor' field, which is of the
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* form of "(v7l)" for an ARMv7-based CPU, and "(v6l)" for
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* an ARMv6-one.
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*/
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if (has_armv7)
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{
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char *cpu_proc = extract_cpuinfo_field(buf, length,
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"Processor");
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if (cpu_proc)
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{
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/* CPU processor and architecture mismatch. */
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if (has_list_item(cpu_proc, "(v6l)"))
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has_armv7 = 0;
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free(cpu_proc);
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}
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}
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if (has_armv7)
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g_cpuFeatures |= CPU_ARM_FEATURE_ARMv7;
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/* The LDREX / STREX instructions are available from ARMv6 */
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if (arch_number >= 6)
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g_cpuFeatures |= CPU_ARM_FEATURE_LDREX_STREX;
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}
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/* Extract the list of CPU features from 'Features' field */
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cpu_features = extract_cpuinfo_field(buf, length, "Features");
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if (cpu_features)
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{
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if (has_list_item(cpu_features, "vfpv3"))
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g_cpuFeatures |= CPU_ARM_FEATURE_VFPv3;
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else if (has_list_item(cpu_features, "vfpv3d16"))
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g_cpuFeatures |= CPU_ARM_FEATURE_VFPv3;
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/* Note: Certain kernels only report NEON but not VFPv3
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* in their features list. However, ARM mandates
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* that if NEON is implemented, so must be VFPv3
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* so always set the flag.
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*/
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if (has_list_item(cpu_features, "neon"))
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g_cpuFeatures |= CPU_ARM_FEATURE_NEON | CPU_ARM_FEATURE_VFPv3;
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}
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if (cpu_features)
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free(cpu_features);
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if (cpu_arch)
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free(cpu_arch);
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if (buf)
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free(buf);
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cpu_features = NULL;
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cpu_arch = NULL;
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buf = NULL;
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}
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cpu_inited_once = true;
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}
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cpu_flags = g_cpuFeatures;
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if (cpu_flags & CPU_ARM_FEATURE_NEON)
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if (check_arm_cpu_feature("neon"))
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{
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cpu |= RETRO_SIMD_NEON;
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#ifdef __ARM_NEON__
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@ -853,9 +718,25 @@ uint64_t cpu_features_get(void)
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#endif
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}
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if (cpu_flags & CPU_ARM_FEATURE_VFPv3)
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if (check_arm_cpu_feature("vfpv3"))
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cpu |= RETRO_SIMD_VFPV3;
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if (check_arm_cpu_feature("vfpv4"))
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cpu |= RETRO_SIMD_VFPV4;
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#if 0
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check_arm_cpu_feature("swp");
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check_arm_cpu_feature("half");
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check_arm_cpu_feature("thumb");
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check_arm_cpu_feature("fastmult");
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check_arm_cpu_feature("vfp");
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check_arm_cpu_feature("edsp");
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check_arm_cpu_feature("thumbee");
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check_arm_cpu_feature("tls");
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check_arm_cpu_feature("idiva");
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check_arm_cpu_feature("idivt");
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#endif
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#elif defined(__ARM_NEON__)
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cpu |= RETRO_SIMD_NEON;
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arm_enable_runfast_mode();
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