newlib-cygwin/newlib/libc/machine/amdgcn/getreent.c

81 lines
2.2 KiB
C

/* get thread-specific reentrant pointer */
#include <reent.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
/* Copied from the HSA documentation. */
typedef struct hsa_signal_s {
uint64_t handle;
} hsa_signal_t;
typedef struct hsa_kernel_dispatch_packet_s {
uint16_t header ;
uint16_t setup;
uint16_t workgroup_size_x ;
uint16_t workgroup_size_y ;
uint16_t workgroup_size_z;
uint16_t reserved0;
uint32_t grid_size_x ;
uint32_t grid_size_y ;
uint32_t grid_size_z;
uint32_t private_segment_size;
uint32_t group_segment_size;
uint64_t kernel_object;
uint64_t reserved2;
hsa_signal_t completion_signal;
} hsa_kernel_dispatch_packet_t;
struct _reent *
__getreent (void)
{
/* Place the reent data at the top of the stack allocation.
s[0:1] contains a 48-bit private segment base address.
s11 contains the offset to the base of the stack.
s[4:5] contains the dispatch pointer.
WARNING: this code will break if s[0:1] is ever used for anything! */
const register unsigned long buffer_descriptor asm("s0");
unsigned long private_segment = buffer_descriptor & 0x0000ffffffffffff;
const register unsigned int stack_offset asm("s11");
const register hsa_kernel_dispatch_packet_t *dispatch_ptr asm("s4");
struct data {
int marker;
struct _reent reent;
} *data;
unsigned long stack_base = private_segment + stack_offset;
unsigned long stack_end = stack_base + dispatch_ptr->private_segment_size * 64;
unsigned long addr = (stack_end - sizeof(struct data)) & ~7;
data = (struct data *)addr;
register long sp asm("s16");
if (sp >= addr)
goto stackoverflow;
/* Stash a marker in the unused upper 16 bits of s[0:1] to indicate that
the reent data is initialized. */
const register unsigned int s1 asm("s1");
unsigned int marker = s1 >> 16;
if (marker != 12345)
{
asm("s_and_b32\ts1, s1, 0xffff");
asm("s_or_b32\ts1, s1, (12345 << 16)");
data->marker = 12345;
__builtin_memset (&data->reent, 0, sizeof(struct _reent));
_REENT_INIT_PTR_ZEROED (&data->reent);
}
else if (data->marker != 12345)
goto stackoverflow;
return &data->reent;
stackoverflow:
write (2, "GCN Stack Overflow!\n", 20);
abort ();
}