ROM Main Page

Page Index

Introduction

This page consolidates all of the ROM and Z-80 related areas of the site, in an effort to bring some more organization and order to the chaos.

ROMs Compared / Checksums

These pages will show the checksums of the various ROMs and identify what version / model they correspond to. The pages also include links on how to check your own ROM CRC.

ROMs Disassembled

These pages disassemble the ROMs and attempt to provide detailed information as to what each line does.

Model I Level 1 ROM

Complete disassembly with line-by-line explanations

Model I Level II ROM Disasembled and Explained

Online interactive web pages

Model /Revision	Year	CRC (ROM A B C)	Link Format
Model I v1.0	1978-20	AE5D DA84 4002	/sub-disassem-rom-m134.htm?v=m1v10
Model I v1.1a	1978-23	AE60 DA45 40E0	/sub-disassem-rom-m134.htm?v=m1v11a
Model I v1.1b	1978-44	AE60 DA45 3E3E	/sub-disassem-rom-m134.htm?v=m1v11b
Model I v1.2	1979-12	AE60 DA45 40BA	/sub-disassem-rom-m134.htm?v=m1v12
Model I v1.3	1980-02	3 ROM: B078 DA45 4006 2 ROM: 8ABD 4006	/sub-disassem-rom-m134.htm?v=m1v13

Source File

Model 1 ROM Source Code which can be compiled - By KiwiSinceBirth

This source code has support for both V1.3 (the default), and V1.2 of the ROMS. For more information on the differences see references below. Several additional (optional) patches can be applied (e.g. FreHD autoboot) be setting a #DEFINE in the code. But ultimately, this can compiled into the actual ROM.

Main Features

Fully Compilable Source Code for Model 1 Level 2 12KB ROMS.
Both 1.3 and 1.2 versions, plus EACA clone hardware.
Several optional patches have been included via #DEFINE

While originally based off a (low quality) disassembly, the following improvements have been made:

Replaced all disassembler generated labels with meaningful labels.
Ensured all jumps (JR and JP) reference valid code labels.
Replaced all $3xxx hardware references with .EQU definitions.
Replaced all $4xxx buffer references with .EQU definitions.
Replaced all $xx byte references with appropriate decimal or ascii values, and/or .EQU definitions.
Replaced all generated op-code with Byte .DB .DW definitions for DataTables/Text/Constants/Etc
Added code documentation from various sources at the code block / function level.
Replaced incorrect op-codes, where Better Else "Trick" was used.

These ROMs can also be somewhat customized as follows:

Directive	Description
#DEFINE VER12	uncomment this to degrade from V1.3 to V1.2 of the ROM.
#DEFINE VER13	this is the default if VER12 is not defined, and doesnt need to be uncommented
#DEFINE EACA80	uncomment to enable Dick Smith System-80 (EACA) hardware support. NOTE: While not mandatory you should also define VER12 since the System-80 ROM was based on V1.2. V1.3 has not been formally tested, but assume should work, and opens ability to also specify FREHDBT. This only targets the core 12kb ROM, and does not include the latter Rom extensions
#DEFINE FREHDBT	Enables the FreHD auto boot feature, i.e. the Auto boot ROM. This requires version 1.3 ROM as a base, please do NOT define VER12 as it is not compatible (it will be ignored anyway) Consider also enabling NMIHARD to ensure reset (on non-floppy machine) will force a reset.
#DEFINE NMIHARD	Set NMI (reset) as always perform a hard reset. Normally on non-floppy systems NMI performs a soft reset returning to the READY> prompt with the basic program intact. This is useful in system without floppy disk to force a full reset (0066h)
#DEFINE LOWCASE	Disable Alpha character translation of letters A-Z,a-z to the values on range 00h to 1Fh. This is useful when a lower case mod is installed, but an alternate video driver has not been installed, or where the font rom on the machine has the alternate characters in the 00h 1Fh range (0471h)
#DEFINE FASTMEM	Speed up startup memory size check by checking first byte of every 256 page, rather than every byte.
#DEFINE BUGFIX5	Fix Error 5 - 08A7H - INT(DoubleValue) rounding
#DEFINE BUGFIX8	Fix Error 8 - 1009H - PRINT USING, - sign at end of field
#DEFINE PATCH	Includes NMIHARD, LOWCASE, FASTMEM, BUGFIX5, and BUGFIX8
#DEFINE SIZE16K	Will pad the end of the rom with $FF to 16KB size. useful if want to append multiple ROM images for used in large 16K paged rom
#DEFINE _EMBED	Strip all HW, and IO routines leaving just BASIC language as standalone code and used in L2 Basic for CP/M

An enhanced ROM is also available which has slightly broken compatibility, but which otherwise include new support, features, and some bug fixes

Directive	Description
#DEFINE NEWBOOT	Enables a new boot routine which asks for "diskette?" when no disk is detected and retries. It also allows for break to be pressed at any time. (Credit : John Swiderski)
#DEFINE FREHDBT	Enables the FreHD auto boot feature, i.e. the Auto boot ROM. This requires version 1.3 ROM as a base, please do NOT define VER12 as it is not compatible (it will be ignored anyway) Consider also enabling NMIHARD to ensure reset (on non-floppy machine) will force a reset.
#DEFINE NOMEMSIZE	Skip user input of Memory Size? override at startup with M key. (Credit : John Swiderski)
#DEFINE FASTMEM	Speed up startup memory size check by checking first byte of every 256 page, rather than every byte.
#DEFINE NMIHARD	Set NMI (reset) as always perform a hard reset. Normally on non-floppy systems NMI performs a soft reset returning to the READY> prompt with the basic program intact. This is useful in system without floppy disk to force a full reset (0066h)
#DEFINE LOWCASE	Disable Alpha character translation of letters A-Z,a-z to the values on range 00h to 1Fh. This is useful when a lower case mod is installed, but an alternate video driver has not been installed, or where the font rom on the machine has the alternate characters in the 00h 1Fh range (0471h)
#DEFINE MSGSTART	Enhanced startup message showing Free Bytes available to BASIC
#DEFINE KEYBOUNCE	Enables the Keyboard debounce routines that where introduced in rev1.3
#DEFINE BUGFIX1	Fix Error 1 - 04F6H - 32 Character Mode Line Length
#DEFINE BUGFIX2	Fix Error 2 - 153EH - Random Number Single Precision Overrun
#DEFINE BUGFIX5	Fix Error 5 - 08A7H - INT(DoubleValue) rounding
#DEFINE BUGFIX7	Fix Error 7 - 0EF2H - Space after type declaration tag
#DEFINE BUGFIX7C	Fix Error 7C - 213DH - Space after TAB token
#DEFINE BUGFIX8	Fix Error 8 - 1009H - PRINT USING, - sign at end of field
#DEFINE BUGFIX11	Fix Error 11 - 2301H - Overflow on Integer FOR loop
#DEFINE BUGFIX13	Fix Error 13 - 1222H - Display of Single Precision Numbers
#DEFINE EACA80	(OPTIONAL) uncomment to enable Dick Smith System-80 (EACA) hardware support. This only targets the core 12kb ROM, and does not include the latter Rom extensions
#DEFINE SIZE16K	(OPTIONAL) Will pad the end of the rom with $FF to 16KB size. useful if want to append multiple ROM images for used in large 16K paged rom

To make room for all this, cassette support has been removed.

Visit his site here.

Model III Level II ROM Disasembled and Explained

Online interactive web pages

Model /Revision	Year	CRC (ROM A B C)	Link Format
Model III Rev A	1980	9639 407C 2B91	/sub-disassem-rom-m134.htm?v=m3v10
Model III Rev B	1980	9639 407C 2EF8	/sub-disassem-rom-m134.htm?v=m3v20
Model III Rev C	1981	9639 407C 2F84	/sub-disassem-rom-m134.htm?v=m3v30
Model III Rev C Updated	1981	9639 407C 2F84	/sub-disassem-rom-m134.htm?v=m3v31
Model III German	1982	9639 407C 10E4	/sub-disassem-rom-m134.htm?v=m3vGerman

Source File

Model III ROM Source Code which can be compiled - By KiwiSinceBirth

Main Features

Fully Compilable Source Code for Model III Level 2 14KB ROMS
Several optional patches have been included via #DEFINE
Based on ROM A = 9639, ROM B = 407C, ROM C = 2EF8

These ROMs can also be somewhat customized as follows:

Directive	Description
#DEFINE VIDEO50	Enable 50Hz Video Support (Affects RTC)
#DEFINE FREHDBT	Enables the FreHD auto boot ROM feature, ie load fre HD at start
#DEFINE FASTMEM	Speed up startup memory size check by checking first byte of every 256 page, rather than every byte.
#DEFINE BUGFIX5	Fix Error 5 - 08A7H - INT(DoubleValue) rounding issue
#DEFINE BUGFIX8	Fix Error 8 - 1009H - PRINT USING, - sign at end of field
#DEFINE BUGFIX28	Fix Error 28 - 034BH - Stack Initialisation Problem
#DEFINE BUGFIX30	Fix Error 30 - 034BH - 32 char Mode, Incompatible Model I code
#DEFINE BUGFIX40	Fix Error 40 - 05D1H - Broken "RON" Printer Status Routine
#DEFINE PATCH	Includes FASTMEM and BUGFIX5 thru BUGFIX40
#DEFINE SIZE16K	Will pad the end of the rom with $FF to 16KB size. useful if want to append multiple ROM images for used in large 16K paged rom

An enhanced ROM is also available which has slightly broken compatibility, but which otherwise include new support, features, and some bug fixes

Directive	Description
#DEFINE FREHDBT	Enables the FreHD auto boot ROM feature, ie load fre HD at start
#DEFINE BUGFIX1	Fix Error 1 - 04F6H - 32 Character Mode Line Length
#DEFINE BUGFIX2	Fix Error 2 - 153EH - Random Number Single Precision Overrun
#DEFINE BUGFIX5	Fix Error 5 - 08A7H - INT(DoubleValue) rounding issue
#DEFINE BUGFIX7	Fix Error 7 - 0EF2H - Space after type declaration tag
#DEFINE BUGFIX7C	Fix Error 7C - 213DH - Space after TAB token
#DEFINE BUGFIX8	Fix Error 8 - 1009H - PRINT USING, - sign at end of field
#DEFINE BUGFIX11	Fix Error 11 - 2301H - Overflow on Integer FOR loop
#DEFINE BUGFIX13	Fix Error 13 - 1222H - Display of Single Precision Numbers
#DEFINE BUGFIX27	Fix Error 27 - 06CCH - Basic Entry Point. Also Fixes 29, 31.
#DEFINE BUGFIX28	Fix Error 28 - 034BH - Stack Initialisation Problem
#DEFINE BUGFIX30	Fix Error 30 - 034BH - 32 char Mode, Incompatible Model I code
#DEFINE BUGFIX32	Fix Error 32 - 0176H - SET should place a graphic on screen
#DEFINE BUGFIX40	Fix Error 40 - 05D1H - Broken "RON" Printer Status Routine
#DEFINE MSGSTART	Enhanced Startup Message
#DEFINE NOMEMSIZE	Skip user input of Memory Size? override at startup with M key. (Credit : John Swiderski)
#DEFINE FASTMEM	Speed up startup memory size check by checking first byte of every 256 page, rather than every byte.
#DEFINE VIDEO50	(OPTIONAL) Enable 50Hz Video Support (Affects RTC)
#DEFINE SIZE16K	(OPTIONAL) Will pad the end of the rom with $FF to 16KB size. useful if want to append multiple ROM images for used in large 16K paged rom

To make room for all this, cassette support has been removed.

Visit his site here.

Model 4 ROMs

Online interactive web pages

Model /Revision	CRC (ROM A B C)	Link Format
Model 4 - Standard Gen 1 60 Hz	9639 407C 1591	http:/www.trs-80.com/sub-disassem-rom-m134.htm?v=m4v10
Model 4 - Standard Gen 2 60 Hz	8F46 407C 48BC	http:/www.trs-80.com/sub-disassem-rom-m134.htm?v=m4v20
Model 4 - French AZERTY	8F65 407C 43AD	http:/www.trs-80.com/sub-disassem-rom-m134.htm?v=m4vFrench
Model 4 - German	8F46 407C 3080	http:/www.trs-80.com/sub-disassem-rom-m134.htm?v=m4vGerman
Model 4 - Network 4 Student Station	8F46 407C 33CB	http:/www.trs-80.com/sub-disassem-rom-m134.htm?v=m4vNetwork
Model 4 - v1 50hz Australia	9639 407C 1587	http:/www.trs-80.com/sub-disassem-rom-m134.htm?v=m4v1AU
Model 4 - v2 50hz Australia	8F46 407C 48B2	http:/www.trs-80.com/sub-disassem-rom-m134.htm?v=m4v2AU