mirror/RetroArch
1
0
Fork 0
mirror of https://github.com/libretro/RetroArch synced 2025-02-06 09:40:06 +00:00
Code Issues Packages Projects Releases Wiki Activity

(libretro-common) features_cpu - reimplement ARM cpu features code

Browse Source
This commit is contained in:
twinaphex 2016-05-13 04:02:08 +02:00
parent af39105c04
commit f20b969165
1 changed files with 70 additions and 189 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

255
libretro-common/features/features_cpu.c
View File

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