Vortex86

The Vortex86 is a computing system-on-a-chip (SoC) based on a core compatible with the x86 microprocessor family. It is produced by DM&P Electronics, but originated with Rise Technology. Vortex86 previously belonged to SiS, which got the basic design from Rise Technology. SiS sold it to DM&P Electronics in Taiwan. Before adopting the Vortex86 series, DM&P manufactured the M6117D, an Intel 386SX compatible, 25–40 MHz SoC. Vortex86 CPUs implement the IA-32 architecture but which instructions are implemented varies depending on the model. Vortex86SX and the early versions of Vortex86 do not have a floating point unit (FPU). Any code that runs on i586 but does not use floating point instructions will run on these models. Any i586 code will run on Vortex86DX and later. Some Linux kernels (by build-time option) emulate the FPU on any CPU that is missing one, so a program that uses i586-level floating point instructions will work on any Vortex86 family CPU under such a kernel, albeit more slowly on a model with no FPU. The more advanced models have FPUs that have i686-level instructions, such as FUCOMI. Code intended for i686 may fail on some models because they lack a Conditional Move (CMOV) instruction. Compilers asked to optimize code for a more advanced CPU (for example the GNU Compiler with its -march=i686 option) generate code that uses CMOV. Linux systems intended to run on i686 are generally not compatible with these Vortex86 models because the GNU C Library, when built for i686, uses a CMOV instruction in its assembly language strcmp function, which its dynamic loader (ld.so) uses. Hence, no program that uses shared libraries can execute. Below are the properties of a Vortex86 original CPU reported by the Linux kernel tool /proc/cpuinfo. Note that this CPU is a later version with an FPU. processor : 0 vendor_id : SiS SiS SiS cpu family : 5 model : 0 model name : 05/00 stepping : 5 cpu MHz : 199.978 fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 1 wp : yes flags : fpu tsc cx8 mmx up bogomips : 399.