1130 - 2250 Character Generation

[mstram]

Hi Mark, Is the character generation implemented for the 2250 emulator ?

If so, do you have any example code ?

I'm trying to work with the information on pages 20-22 of A27-2723-0 "1130 Component Description IBM 2250 Display Unit Model 4

http://www.textfiles.com/bitsavers/pdf/ibm/1130/intf/A27-2723-0_2250_Display_Unit_Model4_1967.pdf)

but so far am not getting any character output. Mike

Here is my code (adapted from the GDU.asm) example :+1: * GDU.ASM - TEST THE 2250 GRAPHICAL DISPLAY UNIT EMULATOR START EQU * XIO LAMPS * light the lamps XIO CONSW * write CONBF to console * WAIT LD INTAD * get address of interrupt svc routine STO L /B
XIO GO * start regeneration WAIT XIO CHAR1 **** Character generation test XIO CONSW LOOP WAIT MDX LOOP CONBF DC /3C00 BSS E 0 CONSW DC CONBF switches input buffer DC /0900 0000 1001 0000 0000 write to console 0900 INTAD DC INTSV INTSV DC 0 * interrupt service routine XIO SENS3 * read DSW and reset interrupts LD TRING+1 * get revert address S THREE * get address of the Y coordinate preceding the jump STO VECY * save it LD I VECY
A JUMP STO I VECY XIO GO * resume BOSC I INTSV * return from interrupt SENS3 DC 0 DC /CF01 * read DSW with interrupt reset * -------------------------------------------------------- LDATA DC /0101 * indicator lamp data DC /1010 BSS E 0 LAMPS DC LDATA DC /C980 * write with modifier = set lamps * -------------------------------------------------------- BSS E 0 CHAR1 DC CDATA DC /C900 CDATA EQU SCML GB CH1 GB CDATA * SCMB * DBS 0,0,0,0 CH1 EQU DC /BF68 DC /D29A * GB CLOOP GIC ,D RVT * 1 011 1 111 0 110 1000 * 1011 1111 0110 BF68 * -------------------------------------------------- BSS E 0 GO DC GDATA DC /c900 * write = start regeneration JUMP DC 10 * y increment on pen hit THREE DC 3 * constant 3 VECY DC 0 * vector's Y address * ------------------------------------------------------ GDATA SGMV * set vector mode SPM /9 * set pen mode: detect and defer GLOOP STMR * start timer MBA 0,0 * set position DBA 500,500 * GB TRING * call triangle subroutine * MBA 700,300
* GB TRING BPOS MBA 453,872 * GB TRING GB GLOOP * repeat TRING SRVT * store revert register DBI 30,0 DBI -15,30 DBI -15,-30 GIC ,D * interrupt if pen detect occurred RVT END START

[markpizz]

Hi Mike, The internals of the IBM1130 environment are completely out of my expertise.

I've passed a request to Brian Knittel (the developer) to hopefully respond to your question.

• Mark

[mstram]

Hi Mark,

Ok, thx, in the meantime, I guess I can take a look at the source and see what I can figure out.

Mike

[pekka-28]

The issue https://github.com/simh/simh/issues/464 contains a sample that displays text. The rendering is incorrect, but the sequencing of the orders can be used as a reference.

As a start, you will need to:

• position the cursor before writing characters,
• restart generation at the end of the interrupt routine,
• switch to the assembler mnemonics to generate the glyphs to avoid the need for explicit return statement, and
• add a terminating NOP2 after the characters are rendered to switch back to vector or point mode.

The instructions and their assembler mnemonics are identified in the following link. There is also information in the more recent 1130 assembler references. http://chiclassiccomp.org/docs/content/computing/IBM/Other/1130/A27-2723-1_2250DisplayUnitModel4_8Sep69.pdf