// For the concurrent garbage collector, the Go compiler implements
// updates to pointer-valued fields that may be in heap objects by
// emitting calls to write barriers. The main write barrier for
// individual pointer writes is gcWriteBarrier and is implemented in
// assembly. This file contains write barrier entry points for bulk
// operations. See also mwbbuf.go.

package runtime

import (
	"internal/abi"
	"internal/goarch"

	"runtime.wasmTruncS":      {Params: []byte{F64}, Results: []byte{I64}},                // x -> int(x)
	"runtime.wasmTruncU":      {Params: []byte{F64}, Results: []byte{I64}},                // x -> uint(x)
	"gcWriteBarrier":          {Params: []byte{I64}, Results: []byte{I64}},                // #bytes -> bufptr
	"runtime.gcWriteBarrier1": {Results: []byte{I64}},                                     // -> bufptr

		// the result should be the PC within f that g will return to.
		// See runtime/stubs.go for a more detailed discussion.
		{name: "LoweredGetCallerPC", reg: gp01, rematerializeable: true},

		// LoweredWB invokes runtime.gcWriteBarrier. arg0=mem, auxint=# of buffer entries needed
		// It saves all GP registers if necessary,
		// but clobbers R1 (LR) because it's a call
		// and R30 (REGTMP).
		// Returns a pointer to a write barrier buffer in R29.

		return
	}

	// Number of write buffer entries we can request at once.
	// Must match runtime/mwbbuf.go:wbMaxEntriesPerCall.
	// It must also match the number of instances of runtime.gcWriteBarrier{X}.
	const maxEntries = 8

	var sb, sp, wbaddr, const0 *Value
	var cgoCheckPtrWrite, cgoCheckMemmove *obj.LSym
	var wbZero, wbMove *obj.LSym
	var stores, after []*Value
	var sset, sset2 *sparseSet

		// the result should be the PC within f that g will return to.
		// See runtime/stubs.go for a more detailed discussion.
		{name: "LoweredGetCallerPC", reg: gp01, rematerializeable: true},

		// LoweredWB invokes runtime.gcWriteBarrier. arg0=mem, auxint=# of buffer entries needed
		// It saves all GP registers if necessary,
		// but clobbers RA (LR) because it's a call
		// and T6 (REG_TMP).
		// Returns a pointer to a write barrier buffer in X24.

	{name: "WBend", argLength: 1, typ: "Mem"},                  // Write barrier code is done, interrupting is now allowed.

	// WB invokes runtime.gcWriteBarrier.  This is not a normal
	// call: it takes arguments in registers, doesn't clobber
	// general-purpose registers (the exact clobber set is
	// arch-dependent), and is not a safe-point.

		{name: "LoweredAtomicOr32", argLength: 3, reg: gpstore, asm: "OR", faultOnNilArg0: true, hasSideEffects: true},

		// LoweredWB invokes runtime.gcWriteBarrier. arg0=mem, auxint=# of buffer entries needed
		// It preserves R0 through R17 (except special registers R1, R2, R11, R12, R13), g, and R20 and R21,
		// but may clobber anything else, including R31 (REGTMP).