HelenOS sources
#
#
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# - Redistributions of source code must retain the above copyright
# - Redistributions in binary form must reproduce the above copyright
# - The name of the author may not be used to endorse or promote products
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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#include <abi/asmtool.h>
#include <libarch/fibril_context.h>
.text
## Save current CPU context
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#
FUNCTION_BEGIN(__context_save)
movl 0(%esp), %eax # the caller's return %eip
movl 4(%esp), %edx # address of the context variable to save context to
movl %esp, __CONTEXT_OFFSET_SP(%edx) # %esp -> ctx->sp
movl %eax, __CONTEXT_OFFSET_PC(%edx) # %eip -> ctx->pc
movl %ebx, __CONTEXT_OFFSET_EBX(%edx) # %ebx -> ctx->ebx
movl %esi, __CONTEXT_OFFSET_ESI(%edx) # %esi -> ctx->esi
movl %edi, __CONTEXT_OFFSET_EDI(%edx) # %edi -> ctx->edi
movl %ebp, __CONTEXT_OFFSET_EBP(%edx) # %ebp -> ctx->ebp
movl %gs:0, %eax
movl %eax, __CONTEXT_OFFSET_TLS(%edx) # tls -> ctx->tls
xorl %eax, %eax # __context_save returns 0
ret
FUNCTION_END(__context_save)
## Restore saved CPU context
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#
FUNCTION_BEGIN(__context_restore)
movl 4(%esp), %eax # address of the context variable to restore context from
movl 8(%esp), %ecx # return value
movl __CONTEXT_OFFSET_SP(%eax),%esp # ctx->sp -> %esp
movl __CONTEXT_OFFSET_PC(%eax),%edx # ctx->pc -> \pc
movl __CONTEXT_OFFSET_EBX(%eax),%ebx # ctx->ebx -> %ebx
movl __CONTEXT_OFFSET_ESI(%eax),%esi # ctx->esi -> %esi
movl __CONTEXT_OFFSET_EDI(%eax),%edi # ctx->edi -> %edi
movl __CONTEXT_OFFSET_EBP(%eax),%ebp # ctx->ebp -> %ebp
movl %edx, 0(%esp) # ctx->pc -> saver's return %eip
movl __CONTEXT_OFFSET_TLS(%eax), %edx # Set arg1 to TLS addr
movl %edx, %gs:0
movl %ecx, %eax
ret
FUNCTION_END(__context_restore)
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