newlib-cygwin/newlib/libc/sys/amdgcn/write.c

114 lines
3.2 KiB
C

/*
* Support file for amdgcn in newlib.
* Copyright (c) 2014, 2017 Mentor Graphics.
*
* The authors hereby grant permission to use, copy, modify, distribute,
* and license this software and its documentation for any purpose, provided
* that existing copyright notices are retained in all copies and that this
* notice is included verbatim in any distributions. No written agreement,
* license, or royalty fee is required for any of the authorized uses.
* Modifications to this software may be copyrighted by their authors
* and need not follow the licensing terms described here, provided that
* the new terms are clearly indicated on the first page of each file where
* they apply.
*/
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
/* This struct must match the one used by gcn-run and libgomp.
It holds all the data output from a kernel (besides mapping data).
The base address pointer can be found at kernargs+16.
The next_output counter must be atomically incremented for each
print output. Only when the print data is fully written can the
"written" flag be set.
The buffer is circular; the host increments the consumed counter
and clears the written flag as it goes, opening up slots for reuse.
The counters always use absolute numbers. */
struct output {
int return_value;
unsigned int next_output;
struct printf_data {
int written;
char msg[128];
int type;
union {
int64_t ivalue;
double dvalue;
char text[128];
};
} queue[1024];
unsigned int consumed;
};
_READ_WRITE_RETURN_TYPE write (int fd, const void *buf, size_t count)
{
if (fd != 1 && fd != 2)
{
errno = EBADF;
return -1;
}
/* The output data is at ((void*)kernargs)[2]. */
#if defined(__has_builtin) && __has_builtin(__builtin_gcn_kernarg_ptr)
register void **kernargs = __builtin_gcn_kernarg_ptr ();
#else
register void **kernargs asm("s8");
#endif
struct output *data = (struct output *)kernargs[2];
/* Each output slot allows 256 bytes, so reserve as many as we need. */
unsigned int slot_count = ((count+1)/256)+1;
unsigned int index = __atomic_fetch_add (&data->next_output, slot_count,
__ATOMIC_ACQUIRE);
if ((unsigned int)(index + slot_count) < data->consumed)
{
/* Overflow. */
errno = EFBIG;
return 0;
}
for (int c = count;
c >= 0;
buf += 256, c -= 256, index++)
{
unsigned int slot = index % 1024;
/* Spinlock while the host catches up. */
if (index >= 1024)
while (__atomic_load_n (&data->consumed, __ATOMIC_ACQUIRE)
<= (index - 1024))
asm ("s_sleep 64");
if (c < 128)
{
memcpy (data->queue[slot].msg, buf, c);
data->queue[slot].msg[c] = '\0';
data->queue[slot].text[0] = '\0';
}
else if (c < 256)
{
memcpy (data->queue[slot].msg, buf, 128);
memcpy (data->queue[slot].text, buf+128, c-128);
data->queue[slot].text[c-128] = '\0';
}
else
{
memcpy (data->queue[slot].msg, buf, 128);
memcpy (data->queue[slot].text, buf+128, 128);
}
data->queue[slot].type = 3; /* Raw. */
__atomic_store_n (&data->queue[slot].written, 1, __ATOMIC_RELEASE);
}
return count;
}