c.FPReg = framepointerRegLOONG64
		c.LinkReg = linkRegLOONG64
		c.hasGReg = true
	case "s390x":
		c.PtrSize = 8
		c.RegSize = 8
		c.lowerBlock = rewriteBlockS390X
		c.lowerValue = rewriteValueS390X
		c.registers = registersS390X[:]
		c.gpRegMask = gpRegMaskS390X
		c.fpRegMask = fpRegMaskS390X
		c.FPReg = framepointerRegS390X
		c.LinkReg = linkRegS390X
		c.hasGReg = true
		c.noDuffDevice = true

		ParamFloatRegNames: "F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15",
		gpregmask:          gp,
		fpregmask:          fp,
		framepointerreg:    -1, // not used
		linkreg:            int8(num["R1"]),
	})

		ParamFloatRegNames: "F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12",
		gpregmask:          gp,
		fpregmask:          fp,
		specialregmask:     xer,
		framepointerreg:    -1,
		linkreg:            -1, // not used
	})

	}
	if buildcfg.FramePointerEnabled && s.f.Config.FPReg >= 0 {
		s.allocatable &^= 1 << uint(s.f.Config.FPReg)
	}
	if s.f.Config.LinkReg != -1 {
		if isLeaf(f) {
			// Leaf functions don't save/restore the link register.
			s.allocatable &^= 1 << uint(s.f.Config.LinkReg)
		}
	}
	if s.f.Config.ctxt.Flag_dynlink {
		switch s.f.Config.arch {
		case "386":
			// nothing to do.

		ParamFloatRegNames: "F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15",
		gpregmask:          gp,
		fpregmask:          fp,
		framepointerreg:    -1, // not used
		linkreg:            int8(num["R30"]),
	})