How can I change SFR (bit) address definition when program is running?

In my application, I want to easily change address of SFR include user's commands. Such as: sbit ram_en=P1^0; ...... /*In another place, I want to change ram_en to P1^2 dynamiclly.*/ I am try...
How can I change SFR (bit) address definition when program is running?

In my application, I want to easily change address of SFR include user's commands. Such as: sbit ram_en=P1^0; ...... /*In another place, I want to change ram_en to P1^2 dynamiclly.*/ I am try...
in C51 ,SFR Bit ??

Programe is following #,,,, sfr p0 = 0x80; sbit p10 = p0^0; sbit p11 = p0^1; void main(void) { ... fc(p10); } void fc(bit bv) { bv=1; ..... // delay bv=0; } but output of p10 is...
in C51 ,SFR Bit ??

Programe is following #,,,, sfr p0 = 0x80; sbit p10 = p0^0; sbit p11 = p0^1; void main(void) { ... fc(p10); } void fc(bit bv) { bv=1; ..... // delay bv=0; } but output of p10 is...
SFR addressing question

Where as all defined SFR's (IE ones that aren't reserved) fit within the range of S:080-S:0FF. So (considering the available IP variants) how can one address or even access S:000-S:07F or S:100-S:1FF...