Month: January 2022

All PGA 386s benchmarked with the UCA

The C&T Super386 being the last of the PGA 386-compatible CPUs ever released to be supported by the Universal Chip Analyzer, it was time to publish some benchmarks! The current integrated benchmark uses a lot of standard x86 operations (mov, add, conditional and unconditional jumps, …) and integer math instructions (add, sub, div, mult). Keep in mind that the UCA can achieve a 0-wait-states-everywhere communication with the CPU, nullifying any added latencies from chipset, RAM, or whatever. The results below are 100% linked to the raw CPU power without any limitation from the subsystem.

First, all 386 compatibles manufacturers which claimed superior performance versus Intel’s 386 actually delivered their promises. AMD’s 386s use the exact same die and consequently offers the same performance. Intel’s own RapidCAD is only 6% faster than the standard 386 on integer operation but comes with an integrated FPU offering much higher speed on floating point operations. The C&T Super386 is significantly faster than Intel’s 386: about 20% higher. C&T claimed its microprocessors were up to 10 percent more powerful than Intel’s, which looks almost correct in real-world applications where added latencies from buses and memory lower the raw gain.

Anyway, the much more advanced Cyrix 486 Core (and its licensed clone from Texas Instrument) takes the lead by a giant margin despite being pin-compatible with the 386 Socket. The slowest Cyrix 486DLC-25 is almost as fast as an Intel/AMD 386 clocked 40 MHz, and the clock-doubled 486DRx2 are twice faster than the fastest Intel 386!

Stay tuned for bigger UCA news tomorrow!

The UCA now supports C&T Super386!

Chips and Technologies (C&T or CHIPS) was a little-known company found in California in 1984. The company first developed one of the first EGA video chipset and some system logic chip sets for IBM’s PC-XT and PC-AT. In September 1991, C&T announced its very first and only x86-compatible CPU: an Intel 386 compatible chip named the “Super386”. It used clean-room implementation process (basically reverse engineering) but Intel sued them almost immediately for patent infringement. Being unable to fight against Chipzilla on a costly trial, the case was settled in 1993, making the Super386 a very short-lived CPU only produced in few quantities in 1992. Later, C&T refocused on laptop graphic chips and was ultimately acquired by Intel in 1997.

Here are the x86-related products from C&T announced in 1991:

    • J38600DX – A PGA CPU pin-compatible with the Intel 386DX at 20, 25, 33 and 40 MHz at $157, $157, $195 and $206. Only the 25 MHz and 33 MHz parts seem to have reached the marked.
    • J38600SX – A 386SX pin-compatible CPU announced in 16MHz, 20MHz and 25MHz versions at $59, $88 and $92 in volume quantities. No retail nor prototypes part ever surfaced.
    • J38605SX/DX – A more advanced 386 with 0.5 KB cache and an innovative feature called SuperState V. Not pin-compatible with Intel 386. Never released but a couple prototypes are known.
    • J38700SX/DX – A 387 math co-processor, by far the more “common” chip of them all. Available in PGA (DX) and QFP (SX) versions at speed ranging from 16 MHz to 40 MHz. Pin compatible with their Intel counterparts.

The Super386 (J38600DX) being the only x86 CPU from Chips and Technologies that reached the stores (albeit in very small quantities), it had to be supported by the UCA!  I was able to finally find one and add support on the UCA!

Running at 25 MHz with a much lower power consumption than the first 386s, the C&T Super386 identifies itself with CPUID 0x300. The same CPUID was used for very early (and very rare) A-Step Intel 386. To distinguish them, you must check for the undocumented 0x0F, 0x18 instruction, only available on the C&T Super386.

I’ll publish some benchmarks tomorrow.

More interesting information about the C&T Super386 can be found here:

 

UCA production postponed due to IC shortage

It’s been quite a long time without any Universal Chip Analyzer news. No worries: I continued to work on the project and added some nice features in the past months. It’s now time to publish some updates. Let’s start with the biggest issue: the final UCA v2 is now ready for production but unfortunately, the global IC shortage is so serious that I’m not able to start producing them right now.

The availability and price for some key components used for the UCA is totally out of control since last summer. The lead time for many ICs is now counted in months, sometimes even more than a year. Prices have gone insane: 2x to 3x increase for DC-DC converters and common MCUs like the ARM Cortex-M0 ATSAMD21 used on the UCA and even much more for the base FPGA.

The exact same FPGA from the same supplier, which I bought $5.9 less than one year ago, now costs $65, an awesome 10x increase! Volume quantities are still available, but from a few brokers (with questionable control quality) and only at indecent prices. Some of them even bought batch of previously assembled boards to salvage the chips and sell them as “used” parts! Based on these crazy prices, a complete UCA (FPGA + IF board without top interface board) would cost in the $200 range, which is way too high to start production.

I’ve studied many workarounds, but unfortunately, none of them can solve the problem quickly. One of the options was to switch from the Spartan-6 line to the newer Spartan-7 or Artix-7 line. Both are still active but unavailable at decent price right now, but I would expect the Xilinx FPGAs based on the 28nm process (7 series) to become available again sooner than the more mature 45nm line (6 series).

While Spartan-6 are not expected to become EOL before 2027 at least, switching to the Spartan-7 will allow access to the newer software development suite from Xilinx (Vivado) instead of the old ISE. On the downside, the higher performance of the Spartan-7 is almost useless in the UCA, they only come in BGA form factor (which is more costly to assemble than the TQFP package used on the Spartan-6) and they also require a much more complex power distribution scheme that will increase the overall BOM by at least $15. To make things even harder, Artix-7/Spartan-7 FPGAs require a much bigger configuration file (bitstream) that will jeopardize the whole programming tricks I use on the UCA. A new MCU based on a more powerful Cortex-M3 will be mandatory to program the FPGA, with bitstreams files (up to 100+ on the UCA!) stored on an SD Card instead of a Flash EEPROM.

All these changes would approximately double the price of the base UCA board without any significant advantage for the end-user. At this time, I’ll stick on the Spartan-6 as they’re the perfect FPGA for the UCA, but I will probably start working on a completely redesigned Spartan-7 base board as a last-resort backup solution.

Here is for the bad thing. Stay tuned for better news tomorrow and even more throughout the week!