Retro68/gcc/libgo/go/runtime/sys_mips64x.go
2017-04-10 13:32:00 +02:00

44 lines
1.4 KiB
Go

// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build mips64 mips64le
package runtime
import "unsafe"
// adjust Gobuf as if it executed a call to fn with context ctxt
// and then did an immediate Gosave.
func gostartcall(buf *gobuf, fn, ctxt unsafe.Pointer) {
if buf.lr != 0 {
throw("invalid use of gostartcall")
}
buf.lr = buf.pc
buf.pc = uintptr(fn)
buf.ctxt = ctxt
}
// Called to rewind context saved during morestack back to beginning of function.
// To help us, the linker emits a jmp back to the beginning right after the
// call to morestack. We just have to decode and apply that jump.
func rewindmorestack(buf *gobuf) {
var inst uint32
if buf.pc&3 == 0 && buf.pc != 0 {
inst = *(*uint32)(unsafe.Pointer(buf.pc))
if inst>>26 == 2 { // JMP addr
//print("runtime: rewind pc=", hex(buf.pc), " to pc=", hex(buf.pc &^ uintptr(1<<28-1) | uintptr((inst&^0xfc000000)<<2)), "\n");
buf.pc &^= 1<<28 - 1
buf.pc |= uintptr((inst &^ 0xfc000000) << 2)
return
}
if inst>>16 == 0x1000 { // BEQ R0, R0, offset
//print("runtime: rewind pc=", hex(buf.pc), " to pc=", hex(buf.pc + uintptr(int32(int16(inst&0xffff))<<2 + 4)), "\n");
buf.pc += uintptr(int32(int16(inst&0xffff))<<2 + 4)
return
}
}
print("runtime: pc=", hex(buf.pc), " ", hex(inst), "\n")
throw("runtime: misuse of rewindmorestack")
}