The S5L8945 is the Apple A5X processor currently used in the "The New iPad", also called iPad (3rd generation).
The processor uses the Cortex-A9 core, and an updated version of the 8940 architecture. S5L8945X also has a new security epoch, but the SoC also has identical caching, and other components as to the 8940. The processor (H4G) runs at 950MHz.
The software architecture as reported by "hostinfo" is: armv7f.
The A5X part number is APL5498 and the die markings repeat that same number as well. It is produced by Samsung with its low power 45nm CMOS process. The die measures 12.82mm × 12.71mm for an area of 162.94mm².
The chip contains Bootrom 1062.2. It runs ARM based instructions. The exact ARM reference has to be determined yet.