The cores were also ARM7 and ARM9, respectively. IIRC, the ARM7 one was essentially identical to the ARM7 used in the GBA, and was used for the GBA backwards c

The cores were also ARM7 and ARM9, respectively. IIRC, the ARM7 one was essentially identical to the ARM7 used in the GBA, and was used for the GBA backwards compatibility mode on the original DS/lite.