notes on hp1653b

gistfile1.txt

Possible memory map:
https://gitlab.com/mamedev/mame/-/blob/mame0226/src/mame/drivers/hp16500.cpp

code starts at 002C in the pvtest file, which is loaded at 0x984500.
Strings are null terminated.

Screen size: 576x368; each logical line is 592 pixels long (16 invisible)

992fe2+2: SetCoordinates:  push y, x
        0098a500 48  78  00       pea        (0xb4 ).w
                 b4
        0098a504 48  78  01       pea        (0x15c ).w
                 5c
        0098a508 4e  93           jsr        (A3 => LAB_00992fe2+2 )
        0098a50a 50  8f           addq.l     #0x8 ,SP

FUN_00993044: args: push string, push length 

FUN_00992ff6: DrawString: push string, zero terminated

FUN_00992fc0: DrawRect:
 push thickness, height, width, y, x
Good test location: 0098a3d6/5f02

LAB_00992fe6+4: DrawChar: push char (.w) to draw

FUN_00992fde.l: SetBold: push word: 1 bold, 0 normal

FUN_00993014: takes two coordinate pairs; line?

0098a078: DrawKeyboard

0098a934: TestKeys

FUN_00993038: get key --> D0 ; probably -1 is none

mod: at 5f00, change 01 56 to 01 FF

at 600000: graphics memory, draw in white by default.
To switch to black:
    move.w     #4 ,-(SP ) ; other values 0,1,FF ;
    jsr        $0000eaba
    addq.l     #2 ,SP
 FF does nothing?!  00 draws black, 04 draws black, 

To turn off writing:
    move.w     #$fe ,-(SP )
    jsr        $0000eaae
    addq.l     #2 ,SP
# f1, f9???

When writing white: 98077c = 00FE, 98077E = FFFE
 FF00 --> 201000 = FFFE black
 mode 0002 or 0003 --> 201000 white 
 write word at a time to even addresses ; only lowest 4 bits matter
 000F draw
 0F0F erase or 000F
Pixels written in black in mode 0000 in black can't be erased to white
without being rewritten in black in mode FF00 first. Very strange!

Draw pixel in SYSTEM_:

void FUN_00a04b12(ushort param_1,ushort param_2)
{
  ushort uVar1;
  
  uVar1 = 8;
  if ((param_1 & 3) != 0) {
    uVar1 = 8 >> (param_1 & 3);
  }
  (x/4)*2 + y*(592/2) = 8 >> (x % 8)
  *(ushort *)((uint)((param_1 & 0xfffc) >> 1) + (uint)param_2 * 0x128 + 0x600000) = uVar1;
  return;
}

// only the last 4 bits of each display byte are used

ead8: rectangle: 7,h,w,y,x ???? not quite

ea06: one arg 1e

eac6: 8,8,170,240 (after 0000eaae : fe) : clears rectangle on screen

eae4: y,x : set coordinates
eaf6: print 0-terminated string
eacc: 2,coordinates,coordinates :  


@eaba:
4ef9000092da4ef90000198e4ef9000014A04EF9000017DA4EF9000018F6
jmp table: 92DA
@92da:
4e56ffc848ee9193ffc833ee00080098077e46790098077e207c0020100030390098077ee14832390098077C100130804Cee0103FFC84E5E4E754E56FFC848EE0007FFC8