#Mac 68040 emulator full
#Mac 68040 emulator software

This new mask was introduced in mid-1995 and converted the 68LC040 chip to MC status. According to Motorola's errata, any chip with a mask set 2E71M or later does not contain the bug.

#Mac 68040 emulator software

Some mask revisions of the 68LC040 contained a bug that prevents the chip from operating correctly when a software FPU emulator is used. Although the CPU now fits into a feature chart more like the Motorola 68030, it continues to include the 68040's caches and pipeline and is thus significantly faster than the 68030. This makes it less expensive and it draws less power. The 68LC040 is a low cost version of the Motorola 68040 microprocessor with no FPU. It differs from the 68040 in that it has neither an FPU nor an MMU. The 68EC040 is a version of the Motorola 68040 microprocessor, intended for embedded controllers (EC). The 68040 offered the same features as the Intel 80486, but on a clock-for-clock basis could significantly outperform the Intel chip in integer and floating point instructions. Overclocking enthusiasts reported success reaching 50В MHz using a 100В MHz oscillator instead of an 80В MHz part and the then novel technique of adding oversized heat sinks with fans. A 50В MHz variant was planned, but canceled. This affected the scaling of the processor and it was never able to run with a clock rate exceeding 40В MHz.

While it delivered over four times the per-clock performance of the 6800, the chip's complexity and power requirements came from a large die and large caches. Heat was always a problem throughout the 68040's life. As this was an exception handler, heavy use of the transcendental functions caused severe performance penalties. The Motorola floating point support package (FPSP) emulated these instructions in software under interrupt. (For information on Motorola's multiprocessing model with the 680x0 series, see Motorola 68020.) The FPU in the 68040 was thus made incapable of IEEE transcendental functions, which had been supported by both the 6882 and were used by the popular fractal generating software of the time and little else.

#Mac 68040 emulator full

Motorola's 68882 external FPU was known as a very high performance unit and Motorola did not wish to risk integrators using the 'LC' version with a 68882 instead of the more profitable full 'RC' unit. While the MMU did not take many transistors-indeed, having it on the same die as the CPU actually saved on transistors-the FPU certainly did. The 68040 ran into the transistor budget limit early in design. The 68040 was also used in other personal computers, such as the Amiga 4000 and Amiga 4000T, as well as a number of workstations, Alpha Microsystems servers, the HP 9000/400 series, and later versions of the NeXT computer. The more expensive models in the (short-lived) Macintosh Centris line also used the 68040, while the cheaper Quadra, Centris and Macintosh Performa used the 68LC040. The fastest 68040 processor was clocked at 40В MHz and it was used only in the Quadra 840AV. In Apple Macintosh computers, the 68040 was introduced in the Macintosh Quadra, which was named for the chip. A planned 50В MHz grade was canceled after it exceeded the thermal design envelope. 25В MHz and 33В MHz grades featured across the whole line, but until around 2000 the 40В MHz grade was only for the 'full' 68040. The 16В MHz and 20В MHz parts were never qualified (XC designation) and used as prototyping samples. Motorola had intended the EC variant for embedded use, but embedded processors during the 68040's time did not need the power of the 68040, so EC variants of the 6800 continued to be common in designs.

Versions of the 68040 were created for specific market segments, including the 68LC040, which removed the FPU, and the 68EC040, which removed both the FPU and MMU. It also had split instruction and data caches of 4 kilobytes each. It thus included all of the functionality that previously required external chips, namely the FPU and Memory Management Unit (MMU), which was added in the 68030. The 68040 was the first 680x0 family member with an on-chip Floating-Point Unit (FPU). In keeping with general Motorola naming, the 68040 is often referred to as simply the '040 (pronounced oh-four-oh or oh-forty). It is the successor to the 68030 and is followed by the 68060. The Motorola 68040 (' sixty-eight-oh-forty') is a 32-bit microprocessor in the Motorola 68000 series, released in 1990. Motorola 68040 die shot with FPU on the left