ped7g’s gists

ped7g / bites2bytes.asm

Created March 22, 2024 19:18

Z80 machine code challenge, turn number of bits into bytes required to store it in C language

	;; original facebook post in "Z80 Assembly Programming On The ZX Spectrum" group:
	; Here's a challenge for your creativity.
	; Create a Z80 assembly function with the following properties:
	; Input in A: values in the range [1,32]
	; Output in A: 1 for 1-8, 2 for 9-16, 4 for 17-32
	; No loops or other conditional jumps.
	; No usage of ROM code.
	; No comparisons.
	; The function will map how many bits an integer needs to how many bytes it needs in a typical C style struct.

ped7g / fb_cauldron.asm

Created March 6, 2024 01:18

"cauldron" logo drawn by attributes for ZX Spectrum, size coding optimization, 40 bytes

	; ZX SPECTRUM code, sjasmplus syntax: https://github.com/z00m128/sjasmplus
	; alternative code for Allan Turvey post: https://www.facebook.com/groups/z80asm/posts/1982356728824612/
	ORG $8000-8
	DEVICE ZXSPECTRUM48, $ - 1
	size_start:
	dg ...#.###
	dg ....####
	dg ...#####
	dg ...#####
	dg ..######

ped7g / quicksort_strings.asm

Created May 9, 2023 22:32

Z80 quicksort of array with pointers to 64 byte long strings

	; Author: Ped7g ; (C) 2022 ; license: MIT / GPL / Public Domain (pick whichever fits best for you)
	; sort array of pointers to 64 char long strings (for example filenames)
	; assembled with: https://github.com/z00m128/sjasmplus/

	DEFINE ORG_ADR $8080 ; using only uncontended faster memory, but smaller buffers

	OPT --syntax=abf : CSPECTMAP "qsorts.map"

	DEVICE ZXSPECTRUM48, ORG_ADR-1
	ORG ORG_ADR

ped7g / constants.i.asm

Created May 4, 2023 10:31

Failed attempt to create band-aid tool to make ZX Next HDMI 50Hz mode timing good-enough for multicolor titles

ped7g / rom_first_int.asm

Last active August 23, 2022 09:25

ZX Spectrum custom ROM to measure time till first /INT signal

	; (C): copyright 2022 Peter Ped Helcmanovsky, license: MIT
	; name: custom ZX Spectrum ROM to measure time until first /INT signal
	; public gist somewhere at: https://gist.github.com/ped7g (search for it)
	;
	; to assemble (with z00m's sjasmplus https://github.com/z00m128/sjasmplus/ v1.20.1+)
	; run: sjasmplus rom_first_int.asm
	;
	; history: 2022-08-23: v1.0 - initial version
	;
	; purpose:

ped7g / AndrewDansbyClearBox

Last active April 18, 2022 13:46

ZX Spectrum Z80 assembly - set "box" on screen to particular attribute value

	; Variations on Andrew's question from FB group, two possible entry points
	; clear_box with HL as char-coordinates or clear_box_adr with HL as attribute address
	clear_box:
	; h = valid character y coordinate
	; l = valid character x coordinate
	; b = width
	; c = height
	; a = attribute to fill
	push af
	ld a,h

ped7g / quicksort.asm

Created March 1, 2022 13:04

Z80 asm quicksort of uint16_t array

	; Author: Ped7g ; (C) 2022 ; license: MIT / GPL / Public Domain (pick whichever fits best for you)
	; assembled with: https://github.com/z00m128/sjasmplus/
	; based on https://github.com/MartinezTorres/z80_babel project, written as comparison
	;
	; Notes for myself about debugging/verification: in CSpect debugger `SAVE "data.bin",from,length`
	; Then `hexdump -v -e '/2 "%u\n"' DATA.BIN > data.txt`. Then compare with `sort -g data.txt`

	DEFINE ORG_ADR $8080 ; using only uncontended faster memory, but smaller buffers

	OPT --syntax=abf : CSPECTMAP "qsort.map"

ped7g / erastothenes2.asm

Last active February 25, 2022 04:08

Z80 asm Erastothenes sieve to calculate prime numbers - part two, hunting for performance

	; Author: Ped7g ; (C) 2022 ; license: MIT / GPL / Public Domain (pick whichever fits best for you)
	; assembled with: https://github.com/z00m128/sjasmplus/
	; based on https://github.com/MartinezTorres/z80_babel project, written as comparison
	;
	; This is second version of the sieve routine (asm-like asm, focusing on performance, hard-wired buffer, etc...)
	; For first C-like version check: https://gist.github.com/ped7g/c55bfa0d55ca13ce029549636cdd1de5
	;
	; sieve routine sieve_a_2 starts around line 110, below test harness

	; comment/uncomment the case you wan to debug:

ped7g / erastothenes.asm

Created February 23, 2022 10:41

Z80 asm Erastothenes sieve to calculate prime numbers

	; Author: Ped7g ; (C) 2022 ; license: MIT / GPL / Public Domain (pick whichever fits best for you)
	; assembled with: https://github.com/z00m128/sjasmplus/
	; based on https://github.com/MartinezTorres/z80_babel project, written as comparison

	; DEFINE ORG_ADR $5D01 ; using maximum memory in zx48 snapshot -> prime numbers: 4339, last prime number 41491
	; DEFINE DO_MAX_BUFFER_CASE ; (4339 primes was with shorter test-code, not last version)

	DEFINE ORG_ADR $8080 ; using only uncontended faster memory, but smaller buffers

	OPT --syntax=abf

ped7g / clockwise32x32char_z80n.asm

Last active February 14, 2022 14:37

ZX Spectrum Next example of optimisations using the Z80N extended instructions

	;-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
	; Author: Ped7g ; (C) 2022 ; license: https://opensource.org/licenses/MIT
	; Z80N (ZX Next) assembly, sjasmplus syntax: https://github.com/z00m128/sjasmplus
	;
	; code-size optimisation based on facebook post with small example showcasing the usage of routines
	;
	; default config of example is doing the counter-clockwise rotation of buffer to screen,
	; flip comment to get clock-wise variant:

	computeULAFromVRamAddress EQU computeULAFromVRamAddressCCW

Peter Ped Helcmanovsky ped7g