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/* IBM_PROLOG_BEGIN_TAG */
/* This is an automatically generated prolog. */
/* */
/* $Source: src/ssx/ssx/ssx_stack_init.c $ */
/* */
/* OpenPOWER OnChipController Project */
/* */
/* Contributors Listed Below - COPYRIGHT 2014,2015 */
/* [+] International Business Machines Corp. */
/* */
/* */
/* Licensed under the Apache License, Version 2.0 (the "License"); */
/* you may not use this file except in compliance with the License. */
/* You may obtain a copy of the License at */
/* */
/* http://www.apache.org/licenses/LICENSE-2.0 */
/* */
/* Unless required by applicable law or agreed to in writing, software */
/* distributed under the License is distributed on an "AS IS" BASIS, */
/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or */
/* implied. See the License for the specific language governing */
/* permissions and limitations under the License. */
/* */
/* IBM_PROLOG_END_TAG */
//-----------------------------------------------------------------------------
// *! (C) Copyright International Business Machines Corp. 2014
// *! All Rights Reserved -- Property of IBM
// *! *** IBM Confidential ***
//-----------------------------------------------------------------------------
/// \file ssx_stack_init.c
/// \brief SSX stack initialization
///
/// The entry points in this file are initialization routines - they are never
/// needed after SSX initialization and their code space could be reclaimed by
/// the application after initialization if required.
///
/// This code was split out from "ssx_init.c" because it may be needed in a
/// thread configuration if threads are being created dynamically. in an
/// interrupt-only configuration it is not needed after \c ssx_initialize().
#include "ssx.h"
/// Initialize a stack area.
///
/// \param stack A pointer to the smallest legal address of the stack. The
/// stack address is modified as the stack is aligned and initialized.
///
/// \param size A pointer to the size of the stack (in bytes). The size is
/// modified as the stack is aligned and initialized. At exit this is the
/// final usable stack area size aligned to the size of the SSX_STACK_TYPE.
///
/// SSX makes no assumptions about size or alignment of the area provided as a
/// stack, and carefully aligns and initializes the stack. Regardless of how
/// the stack grows, the \a stack parameter is considered to be the lowest
/// legal address of the stack.
int
__ssx_stack_init(SsxAddress *stack,
size_t *size)
{
SsxAddress mask;
size_t excess, i, count;
SSX_STACK_TYPE *p;
if (SSX_STACK_DIRECTION < 0) {
// Stacks grow down. The initial stack pointer is set to just above
// the last allocated stack address. This is legal for pre-decrement
// stacks, otherwise the initial address is first brought into range
// before alignment. The stack is aligned downward, then the size is
// adjusted to a multiple of the stack type. Stacks are optionally
// prepatterned. Alignment is assumed to be a power of 2.
*stack += *size;
if (!SSX_STACK_PRE_DECREMENT) {
*stack -= sizeof(SSX_STACK_TYPE);
*size -= sizeof(SSX_STACK_TYPE);
}
mask = SSX_STACK_ALIGNMENT - 1;
excess = *stack & mask;
*stack -= excess;
*size -= excess;
*size = (*size / sizeof(SSX_STACK_TYPE)) * sizeof(SSX_STACK_TYPE);
if (SSX_STACK_CHECK) {
p = (SSX_STACK_TYPE *)(*stack);
count = *size / sizeof(SSX_STACK_TYPE);
for (i = 0; i < count; i++) {
if (SSX_STACK_PRE_DECREMENT) {
*(--p) = SSX_STACK_PATTERN;
} else {
*(p--) = SSX_STACK_PATTERN;
}
}
}
__ssx_stack_create_initial_frame(stack, size);
} else {
SSX_PANIC(SSX_UNIMPLEMENTED);
}
return SSX_OK;
}
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