Sweet16 wozniak12/25/2022 ![]() ![]() It shows that code density of modern RISC CPUs is way behind where it could be. Sweet 16 is an impressive example for high code density.Ħ bytes for a memcpy routine! Try that on modern processors.Īnd also note that this code would work the same way in a 32-bit or 64-bit environment. SWEET16s Hidden Potential: Paul Hagstrom: A look at SWEET16, Steve Wozniaks 6502 dream machine. The code can of course be ported to any other processor or written in C.ĠB RS (Return from Subroutine - Stay in Sweet16 mode The high byte of the address to be identical) On the 6502, an 8-bit Jumptable was used, which required all relevant code to be located in the same page (meaning SWEET16 is an interpreted byte-code instruction set invented by Steve Wozniak and implemented as part of the Integer BASIC ROM in the Apple II series of computers. However, the code can use any other range.įor program space, about 300 bytes are required for the implementation on the 6502. When the Sweet16 RTN instruction is executed, execution returns to the following 6502 code. It is embedded in 6502 code by making a call to the Sweet16 subroutine and then executing the following embedded Sweet16 code. In the original Apple implementation, the first 32 bytes located from $0 -$1F were used, 'Sweet16' is Steve Wozniak's compact virtual machine for concisely handling 16bit data on the 6502 processor. SWEET16 requires storage in the zero page area for the registers. For more information on SWEET16, see Memory allocation Despite its simplicity, Sweet 16 achieved an amazing code density, which is still hard to beat today. 6502 assembler and Sweet 16 could be mixed easily: Sweet 16 code was inlined and simply preceeded by a function call to the executer, which was located at a known address (0xF689 or in Apple speech $F689) could easily be started by a subroutine call. ![]() a small virtual machine called Sweet 16 to support 16-bit integers. The Sweet 16 executer was implemented in the ROM of the original Apple ][. The first program that Wozniak tested on the Apple Is BASIC interpreter was an. It was to manipulate 16-bit pointer data from an. Typical programs written in SWEET-16 needed about half the size and 5 to 10 times as much time as pure 6502 assembly code. It was a hybrid computer using what they called Sweet 16 a byte language developed by Steve Wozniak. It required 32-bytes in the Zero page of the 6502, to hold the values of these registers and needed less instructions than the 6502 for most programs. R13 – stores the result of all comparison operations.Some registers have well-defined functions: The language in the trade deals echoes those provisions but contains some differences.SWEET16 has 16 internal 16-bit registers, named R0. Those rules are largely credited with fueling Silicon Valley’s rapid growth. The American rules, codified in Section 230 of the Communications Decency Act, shield online platforms from many lawsuits related to user content and protect them from legal challenges stemming from how they moderate content. American negotiators have proposed including the language in other prospective deals, including with the European Union, Britain, and members of the World Trade Organization. Section 230 Going Into Trade Deals (NYT) - The protections, which stem from a 1990s law, have already been tucked into the administration’s two biggest trade deals-the United States-Mexico-Canada Agreement and a pact with Japan that President Trump signed on Monday. ![]()
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