This paper describes a low-power Intel ® Architecture (IA) processor specifically designed for Mobile Internet Devices (MID) and UltraMobile PCs (UMPC) where average power consumed is in the order of a few hundred mW (as measured by MobileMark'05 OP @ 60 nits brightness) with performance similar to mainstream Ultra-Mobile PCs. The design consists of an in-order pipeline capable of issuing 2 instructions per cycle supporting 2 threads, 32KB instruction and 24KB data L1 caches, independent integer and floating point execution units, ×86 front end execution unit, a 512KB L2 cache and a 533 MT/s dual-mode (GTL and CMOS) front-side-bus (FSB); a block diagram is shown in Fig. 13.1.1. The design contains 47M transistors in a die size under 25mm 2 manufactured in a 9-metal 45nm CMOS process with optimized transistors for low leakage [1] packaged in a Halide-Free 441 ball, 14×13mm 2 μFCBGA. Thermal Design Power (TDP) consumption is measured at 2W using a synthetic power-virus test at a frequency of 2GHz.Features in this new micro-architecture are selected with low power and high performance per watt efficiency in mind. The pipeline is tailored to execute IA instructions as single atomic operations consisting of a single destination register and up to three source-registers and adheres to the Load-Op-Store instruction format. Further, using power efficient algorithms in areas like instruction decoding and scheduling (traditionally complex circuits that are power hungry) achieves high performance per watt efficiency. In addition, support for Hyper-threading technology (HT) is added; the instruction scheduling logic can find a pair of instructions from either the same thread or across threads in a given cycle to dispatch. HT is a feature that provides high performance per watt (typically 30% increases in performance for a 15% increase in power) efficiency in an in-order pipeline. Moreover, the use of specialized execution units is minimized. For example, the SIMD integer multiplier and Floating Point divider are used to execute instructions that would normally require a dedicated scalar integer multiplier and integer divider respectively. Finally, other features like activity-based control of instruction issue and dispatch of operations on the Front Side Bus are added for power reduction. This design uses a "sea-of-Functional-Unit-Blocks (FUB)" methodology whereby all cluster hierarchies as well as all unit-level hierarchies are flattened at the chip-level even though the logical partitioning of the chip-level RTL model is comprised of several logical clusters (Floating Point, Integer Execution, Memory Execution, Front-End, Bus Interface, and L2 Cache). This methodology essentially removes all cluster and unit-level hierarchical boundaries resulting in a physical hierarchy where an object-based parallel editing scheme is used for physical design convergence; Fig. 13.1.7 shows the die photo with the logical unit partitions. The physical database consists of 205 unique FUBs (not including repeater stations) and 41K FUB-to-FUB...

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This paper describes a low power Intel® Architecture (IA) processor specifically designed for Mobile Internet Devices (MID). The design consists of an in-order pipeline capable of issuing 2 instructions per cycle supporting 2 threads, 32KB instruction and 24KB data L1 caches, independent integer and floating point execution units, a 512KB L2 cache and a 533 MT/s dual-mode (GTL and CMOS) frontside-bus (FSB). The design contains 47 million transistors in a die size under 25 mm 2 manufactured in a 9-metal 45nm CMOS process. Thermal design power (TDP) consumption is measured at 2W, 1.0V, 90 o C using a synthetic power-virus test at a frequency of 1.86GHz.

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