subsonic-tui/vendor/github.com/ebitengine/purego/syscall.go

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// SPDX-License-Identifier: Apache-2.0
// SPDX-FileCopyrightText: 2022 The Ebitengine Authors
//go:build darwin || freebsd || linux || windows
package purego
const (
maxArgs = 9
numOfFloats = 8 // arm64 and amd64 both have 8 float registers
)
// SyscallN takes fn, a C function pointer and a list of arguments as uintptr.
// There is an internal maximum number of arguments that SyscallN can take. It panics
// when the maximum is exceeded. It returns the result and the libc error code if there is one.
//
// NOTE: SyscallN does not properly call functions that have both integer and float parameters.
// See discussion comment https://github.com/ebiten/purego/pull/1#issuecomment-1128057607
// for an explanation of why that is.
//
// On amd64, if there are more than 8 floats the 9th and so on will be placed incorrectly on the
// stack.
//
// The pragma go:nosplit is not needed at this function declaration because it uses go:uintptrescapes
// which forces all the objects that the uintptrs point to onto the heap where a stack split won't affect
// their memory location.
//
//go:uintptrescapes
func SyscallN(fn uintptr, args ...uintptr) (r1, r2, err uintptr) {
if fn == 0 {
panic("purego: fn is nil")
}
if len(args) > maxArgs {
panic("purego: too many arguments to SyscallN")
}
// add padding so there is no out-of-bounds slicing
var tmp [maxArgs]uintptr
copy(tmp[:], args)
return syscall_syscall9X(fn, tmp[0], tmp[1], tmp[2], tmp[3], tmp[4], tmp[5], tmp[6], tmp[7], tmp[8])
}