// 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 RA (LR) because it's a call
		// and T6 (REG_TMP).
		// Returns a pointer to a write barrier buffer in X24.

	ir.Syms.Duffzero = typecheck.LookupRuntimeFunc("duffzero")
	ir.Syms.GCWriteBarrier[0] = typecheck.LookupRuntimeFunc("gcWriteBarrier1")
	ir.Syms.GCWriteBarrier[1] = typecheck.LookupRuntimeFunc("gcWriteBarrier2")
	ir.Syms.GCWriteBarrier[2] = typecheck.LookupRuntimeFunc("gcWriteBarrier3")
	ir.Syms.GCWriteBarrier[3] = typecheck.LookupRuntimeFunc("gcWriteBarrier4")
	ir.Syms.GCWriteBarrier[4] = typecheck.LookupRuntimeFunc("gcWriteBarrier5")

	{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).

		{name: "LoweredAtomicOr32Variant", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true},

		// LoweredWB invokes runtime.gcWriteBarrier. arg0=mem, auxint=# of buffer entries needed
		// It saves all GP registers if necessary,
		// but clobbers R30 (LR) because it's a call.
		// R16 and R17 may be clobbered by linker trampoline.

		}

	case ssa.OpPPC64LoweredWB:
		p := s.Prog(obj.ACALL)
		p.To.Type = obj.TYPE_MEM
		p.To.Name = obj.NAME_EXTERN
		// AuxInt encodes how many buffer entries we need.
		p.To.Sym = ir.Syms.GCWriteBarrier[v.AuxInt-1]

	case ssa.OpPPC64LoweredPanicBoundsA, ssa.OpPPC64LoweredPanicBoundsB, ssa.OpPPC64LoweredPanicBoundsC:
		p := s.Prog(obj.ACALL)
		p.To.Type = obj.TYPE_MEM
		p.To.Name = obj.NAME_EXTERN