# Copyright (c) 2021, RISC OS Open Ltd
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LDF_STF(P,UD,T1,Wb,LS,Rn,T0,offset)
{
	/* Packed decimal formats are always handled by FPEmulator, so
	   we only need to worry about the much easier single, double &
	   extended formats. For ultra simplicity, we'll just map everything
	   to a MemMap request and then re-execute the instruction. */
	int len = (T0<<2)+(T1<<3)+4;
	if (len == 16) /* P/EP */
		return aborttrap_ERROR(Unexpected);

	uint32_t base;
	if (!aborttrap_reg_read_current(ctx,Rn,&base))
		return aborttrap_ERROR(BadReg);
	uint32_t offset32 = (UD?offset<<2:-offset<<2);
	/* Undo any base register update */
	bool restore_base = Wb && !(g_ProcessorFlags & CPUFlag_BaseRestored);
	if (restore_base)
		base -= offset32;
	/* Calculate target address */
	uint32_t addr = (P?base+offset32:base);
	_kernel_oserror *e = aborttrap_MemMap(ctx,addr,len,3,LS?AbortTrap_MemMap_UserR:AbortTrap_MemMap_UserW);
	if (!e && restore_base)
	{
		/* Write back the restored base register */
		aborttrap_reg_write_current(ctx,Rn,base);
	}
	return e;
}

LFM_SFM(P,UD,N1:N0,Wb,LS,Rn,offset)
{
	/* Like LDF/STF, take the easy route and convert it to a MemMap
	   request */
	int len = N1_N0;
	if (!len)
		len = 4;
	len *= 12;

	uint32_t base;
	if (!aborttrap_reg_read_current(ctx,Rn,&base))
		return aborttrap_ERROR(BadReg);
	uint32_t offset32 = (UD?offset<<2:-offset<<2);
	/* Undo any base register update */
	bool restore_base = Wb && !(g_ProcessorFlags & CPUFlag_BaseRestored);
	if (restore_base)
		base -= offset32;
	/* Calculate target address */
	uint32_t addr = (P?base+offset32:base);
	_kernel_oserror *e = aborttrap_MemMap(ctx,addr,len,3,LS?AbortTrap_MemMap_UserR:AbortTrap_MemMap_UserW);
	if (!e && restore_base)
	{
		/* Write back the restored base register */
		aborttrap_reg_write_current(ctx,Rn,base);
	}
	return e;
}