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construct/ircd/ctx_x86_64.S

61 lines
2.6 KiB
ArmAsm

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2019 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
// This unit contains customization and experimentation for the core context
// switching routines. First note that everything here is platform-specific
// and not implemented on all platforms. Furthermore, boost::context functions
// overriden here are also overriden for the entire address space; if other
// libraries use boost::context our code will hook their context switches
// which we might not want. All of this must be considered to build or change
// any functionality from here.
#include <ircd/config.h>
#if defined(__x86_64__) && defined(__ELF__)
.file "ctx_x86_64.S"
.globl jump_fcontext
.text
.type jump_fcontext, @function
.align 16
// returns struct transfer_t { void *fctx, *data; };
// param DI = void *to
// param SI = void *vp
jump_fcontext:
push %rbp // store rbp 0x30
push %rbx // store rbx 0x28
push %r15 // store r15 0x20
push %r14 // store r14 0x18
push %r13 // store r13 0x10
push %r12 // store r12 0x08
subq $0x08, %rsp // alloc fc_mxcsr | fc_x87_cw
// fnstcw 0x04(%rsp) // store x87 control-word
// stmxcsr 0x00(%rsp) // store MMX control- and status-word
xchgq %rsp, %rdi // swap stack
movq %rsi, %rdx // store transfer_t.data (retval)
movq %rdi, %rax // store transfer_t.fctx (retval)
// ldmxcsr 0x00(%rsp) // load MMX control- and status-word
// fldcw 0x04(%rsp) // load x87 control-word
addq $0x08, %rsp // free fc_mxcsr | fc_x87_cw
pop %r12 // load r12 <-- LLd miss
pop %r13 // load r13
pop %r14 // load r14
pop %r15 // load r15
pop %rbx // load rbx
pop %rbp // load rbp <-- LLd miss
retq // enter context
// mark the size of jump_fcontext
.size jump_fcontext, .-jump_fcontext
// Mark that we don't need executable stack.
.section .note.GNU-stack, "", %progbits
#endif