linux - 割り込みを無効にするための GICD_ISENABLER と GICD_ICENABLER の違い

Question

GIC マニュアルに従って、GICD_ISENABLER

Reads 
0 Forwarding of the corresponding interrupt is disabled. 
1 Forwarding of the corresponding interrupt is enabled.
Writes 
0 Has no effect.
1 Enables the forwarding of the corresponding interrupt.

GICD_ICENABLER

Reads 
0 Forwarding of the corresponding interrupt is disabled.
1 Forwarding of the corresponding interrupt is enabled.
Writes 
0 Has No Effect
1 Disables the forwarding of the corresponding interrupt

レジスターは2つ必要ですか？目的は 1 で解決できますか。