New PDF release: 40 Best Machine Code Routines for the ZX Spectrum

By John Hardman, Andrew D. Hewson

ISBN-10: 0810451670

ISBN-13: 9780810451674

ISBN-10: 0895880571

ISBN-13: 9780895880574

ISBN-10: 0907912036

ISBN-13: 9780907912033

Show description

Read or Download 40 Best Machine Code Routines for the ZX Spectrum PDF

Best nonfiction_13 books

Download PDF by Brooks Irving Mendell: Protect Yourself Secret of Unarmed Defense

In perfecting the program of self-defense in hand-to-hand wrestle, it's been the writers objective to make on hand to a person an easy set of safeguard measures designed for use in any emergency the place ones individual is at risk of actual attack. totally defined either in images and phrases within the pages of this publication, those holds and throws provide help to guard yourself from the tips of jujitsu, judo, mugging, and all different types of actual assault.

Recent Contributions in Intelligent Systems by Vassil Sgurev, Ronald R. Yager, Janusz Kacprzyk, Krassimir PDF

This quantity is a short, but complete account of latest improvement, instruments, innovations and ideas within the widely perceived “intelligent systems”. New innovations and ideas crisis the advance of powerful and effective types which might give the chance to successfully and successfully describe and resolve procedures in a variety of parts of technological know-how and expertise.

Extra resources for 40 Best Machine Code Routines for the ZX Spectrum

Example text

At `subtract', if (c-1) is a multiple of 64, 1792 is subtracted from de, so that de points to the next block of 64 lines. If c does not hold one, the routine jumps to `next line', otherwise the routine returns to BASIC. 56 6. DISPLAY ROUTINES Merge Pictures Length: 21 Number of Variables: 1 Check sum: 1709 Operation This routine merges a picture stored in RAM (using the `Copy' routine elsewhere in this book) with the current screen display. The attributes are not changed. Variables Name Length Location screen store Comment 2 23296 address in RAM of stored picture Call RAND USR address Error Checks None Comments To merge pictures the routine should be used as listed.

Consider any bit B 2 of byte B, in Figure B1. The data held at the location (B 2 , B,) in the matrix will be Each byte of the rotated character will be built up one at a time, by adding the values of all the bits N 2 that will be in the new byte. The hl register is loaded with the address of the first byte of the character in RAM. The e register is loaded with the value of the byte which has bit 7 on and bits 0-6 off ie 128. The hl register is saved on the stack. The c register, to which data will be added giving the new value of the byte being built, is loaded with zero.

The squares represent illuminated pixels, x marks the starting position within the area to be shaded and * marks the rightmost pixels of RUNS. FA j j j j j j ^ 0 j 0 j 7 ^ j j rzz j Ô j j A j * * * * j A A * * * A Figure B2. An illustration of the techn ique used for filling a region. Grey squares are already illuminated and define the region to be shaded. X is the starting position, * are the starts of RUNS and O remain unshaded. How it works This routine plots horizontal lines of adjacent pixels called `RUNS' within areas bounded by illuminated pixels.

Download PDF sample

40 Best Machine Code Routines for the ZX Spectrum by John Hardman, Andrew D. Hewson

by Christopher

Rated 4.23 of 5 – based on 40 votes