- #Apple gentle reader code#
- #Apple gentle reader plus#
- #Apple gentle reader free#
- #Apple gentle reader mac#
Multi package modules are relatively new: each chip is in its own package, but use very tight pin spacings and do not have a heat spreader. The amount of testing which can be done on a raw die is rather limited, so MCM yields suffer as one bad die ruins the whole assembly. Multi chip modules have been around for a long time, where multiple dies wired together in one big package. This is a multi package module with CPU, I/O chip, and SDRAM sandwiched tightly together. The CPU in the iPhone 3GS is a Samsung S5PC100. When the GPUs are less busy, the ARM clock speed can be brought back up.
Apple has the option to dynamically throttle the ARM clock speed in order to open up more thermal envelope for the GPUs, if sufficient OpenCL workload is ready to run.
#Apple gentle reader plus#
For example: a very large GPU plus very fast ARM would generate more heat than can be dissipated in a small form factor like a phone. By controlling the complete platform from CPU to software, Apple can make tradeoffs which are not practical for the rest of the market. Apple has greater ambitions, and could make use of significantly more GPU pipelines. The rest of the mobile industry is satisfied to offload 3D graphics and video decoding to the GPU. I suspect this is the most compelling reason for Apple to build its own chip as opposed to buying off the shelf.
#Apple gentle reader free#
Apple does not allow iPhone apps to include their own virtual machine in this way, but would be free to provide the VM function as part of the OS. Devices with less sophisticated GPUs would use the ARM instead. If the hardware has sufficient GPU power, the bytecode could be translated to the GPU instruction set and offloaded.
IPhone applications are compiled to ARM instructions, but it is not much of a stretch to imagine support for sections of LLVM bytecodes as well. The compilation can be done statically before running it, or by a Just-In-Time compiler while interpreting the LLVM bytecodes.
#Apple gentle reader code#
Source code can be compiled to the LLVM virtual machine, and from there be translated into the equivalent opcodes for the target CPU. LLVM is a compiler toolkit, one aspect of which is a machine independent instruction set.OpenCL algorithms are written in a language with syntax very similar to C99, and the framework handles the rest. OpenCL allows processing to be distributed across multiple CPUs in the system, even if they have different instruction sets.Additional information can be downloaded after registration.Īpple has also invested heavily in two relevant technologies: OpenCL and LLVM. Update: PowerVR SGX does not use the META architecture, it has a distinct architecture of its own. There is relatively little information about its instruction set on the web, only that it is called META MTX and uses 16 bit RISC-ish instruction words. As with essentially all GPU designs today, the PowerVR makes use of multiple, specialized CPU cores. The A4 chip will certainly integrate a graphics core from PowerVR. Apple uses their PowerVR SGX 535 in iPhone 3GS, and used various PowerVR graphics in earlier iPhone models. With that as background, what might Apple have done in the A4 chip? I have absolutely no inside information about the iPad or A4 processor, I'm going to make stuff up because its fun to speculate.Īpple holds a nearly 10% stake in Imagination Technologies Group, which designs the PowerVR graphics accelerator and other IP relating to massively threaded processing. So far as I know, x86 Macintoshes no longer use custom Apple ASICs.Ĭustom chip design isn't a radical departure for Apple. The x86 bus interface is difficult to license, and Intel's own chipsets are quite reasonable. With the switch to x86, Apple's efforts became much more constrained.
#Apple gentle reader mac#
Apple licensed a gigabit Ethernet MAC design from Sun, and used it plus IDE controller and other peripherals in chipsets for several Powermac models. Later, Apple designed entire chipsets to interface with the PowerPC 60x bus. Apple produced custom silicon for various Macintosh models since at least the late 1980s, when they designed the audio chips used in the Quadra 700 and 900 (a chip called "Batman"). Today, Gentle Reader, we'll explore that notion a bit.Īpple has a long history of ASIC design. It has also been asserted that because the same core is used in parts from Samsung, TI, and Qualcomm, Apple should not have bothered making its own chip. I have no reason to dispute this assertion, it seems like a fine choice. It has been widely assumed that A4 uses a licensed ARM Cortex A8 core. We'll focus on Apple's A4, a custom CPU first used in the iPad. No, don't run away! This will be different, I promise. What the web needs right now is another blog post about the iPad.