From d9be3278f5d0c93b59033286ac5e2d30f5dff6bc Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ond=C5=99ej=20Hru=C5=A1ka?= Date: Tue, 20 Oct 2020 00:53:43 +0200 Subject: [PATCH] docs for float --- README.md | 127 +++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 126 insertions(+), 1 deletion(-) diff --git a/README.md b/README.md index fc2dcc7..64debf8 100644 --- a/README.md +++ b/README.md @@ -169,7 +169,8 @@ This document uses the following notation for arguments: - `NUM` - literal values - unsigned `123` - signed `-123` - - float `-45.6789` + - float `-45.6789`. For now, you must use literals with a period to enter float literals, integers will not be converted to + float when used in floating point instructions! - hex `0xabcd`, `#abcd` - binary `0b0101` - character `'a'`, `'🐁'`. Supports unicode and C-style escapes. Use `\\` for a literal backslash. @@ -428,6 +429,17 @@ Many instructions have two forms: (mod Wr Rd Rd'divider) (mod RW Rd'divider) +; Get abs value +(abs Wr Rd) +(abs RW) + +; Get signum +(sgn Wr Rd) +(sgn RW) + +; Power - e.g. (pow r0 2 8) is 256 +(pow Wr Rd Rd'pow) + ; Swap the 32-bit halves of a value ; 0x01234567_89abcdef -> 0x89abcdef_01234567 (sw32 Wr Rd) @@ -515,6 +527,119 @@ Many instructions have two forms: (del @Rd) ``` +### Floating Point Arithmetics + +The arithmetics module has support for floating point values. There are some gotchas though: + +- Floating point is simply the binary representation of it in an unsigned integer register. + I thought of adding special float registers for this, but then you can't easily pass floats + to subroutines, push them on a stack etc. Not worth it. +- To enter a float literal, always use the notation with a decimal point. It should support minus and scientific notation too. +- There are special instructions dedicated to working with floats. The regular integer instructions + will happily work with their binary forms, but that's absolutely not what you want. + +``` +(itf r0 1.0) ; NO!!! it is already float, what are you doing +(ld r0 1.0) ; okay +(itf r0 1) ; also okay + +(fmul r0 2) ; NO!!!!!!!!!!!!! 2 is not float +(mul r0 2.0) ; ALSO NO!!!!!!!!!!!!! mul is not a float instruction! +(fmul r0 2.0) ; good +``` + +You have to be a bit careful, that's all. + +Here's an abridged summary of the floating point submodule: + +(most of these support the shorthand version too - `RW` in place of `Wr Rd`) + +``` +; IntToFloat +(itf Wr Rd) +; FloatToInt (round) +(fti Wr Rd) +; FloatToInt (ceil) +(ftic Wr Rd) +; FloatToInt (floor) +(ftif Wr Rd) + +; FloatTest - nan->invalid, infinities->overflow, positive, negative, zero +(ftst Rd) +; FloatCompare +(fcmp Rd Rd) +; FloatRangeTest +(fcmpr Rd Rd'min Rd'max) + +; FloatRng +(frng Wr Rd'min Rd'max) + +; --- Basic float arith --- + +; FloatAdd +(fadd Wr Rd Rd) +; FloatSub +(fsub Wr Rd Rd) +; FloatMul +(fmul Wr Rd Rd) +; FloatPow +(fpow Wr Rd Rd'pow) +; FloatRoot +(froot Wr Rd Rd'root) +; FloatHyp +(fhyp Wr Rd Rd) +; FloatDiv +(fdiv Wr Wr'rem Rd'a Rd'div) +; FloatMod +(fmod Wr Rd'a Rd'div) +; FloatAbs +(fabs Wr Rd) +; FloatSgn +(fsgn Wr Rd) + +; --- Basic trig --- + +; FloatSin +(fsin Wr Rd) +; FloatAsin +(fasin Wr Rd) +; FloatCos +(fcos Wr Rd) +; FloatAcos +(facos Wr Rd) +; FloatTan +(ftan Wr Rd) +; FloatAtan +(fatan Wr Rd) +; FloatAtan2 +(fatan2 Wr Rd'y Rd'x) +; FloatCot +(fcot Wr Rd) +; FloatAcot +(facot Wr Rd) + +; --- Hyperbolic trig --- + +; FloatHypSin +(fsinh Wr Rd) +; FloatHypAsin +(fasinh Wr Rd) +; FloatHypCos +(fcosh Wr Rd) +; FloatHypAcos +(facosh Wr Rd) +; FloatHypTan +(ftanh Wr Rd) +; FloatHypAtan +(fatanh Wr Rd) +; FloatHypCot +(fcoth Wr Rd) +; FloatHypAcot +(facoth Wr Rd) +``` + +Wow, thats a lot. I didn't test many of these yet. There may be bugs. + ## Buffers Module This module defines dynamic size integer buffers.