CINT should be complete now
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@@ -102,8 +102,8 @@ NOTE: Even the 'DONE' routines won't support features described as missing in on
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| Address | Unofficial | Name | Status | Remarks |
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| :-------: | :--------: | :---------- | :------: | :--------------------------------------------------: |
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| `($028F)` | | `KEYLOG` | DONE | |
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| `$FF81` | `$FF5B` | `CINT` | PARTIAL | probably incomplete, needs adjustments for compat. |
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| `$FF84` | `$FDA3` | `IOINIT` | PARTIAL | CIA initialization incomplete |
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| `$FF81` | `$FF5B` | `CINT` | DONE | |
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| `$FF84` | `$FDA3` | `IOINIT` | PARTIAL | CIA initialization might be incomplete |
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| `$FF87` | `$FD50` | `RAMTAS` | PARTIAL | probably shouldn't touch VIC and CIA's |
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| `$FF8A` | `$FD15` | `RESTOR` | DONE | |
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| `$FF8D` | `$FD1A` | `VECTOR` | DONE | |
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@@ -157,7 +157,8 @@ Not all of them - only these we want to have implemented.
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| Address | Name | Status | Remarks |
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| :-------: | :--------------------------- | :------: | :------------------------------------------------: |
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| `$E51B` | init screen keyboard, no VIC | PARTIAL | not sure if correct |
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| `$E518` | legacy part of CINT | DONE | |
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| `$E51B` | init screen keyboard, no VIC | DONE | |
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| `$E544` | clear screen | DONE | |
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| `$E50C` | set cursor position | PARTIAL | |
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| `$E566` | home cursor | NOT DONE | |
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+2
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@@ -1,62 +1,12 @@
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//
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// It seems this is a part CINT which initializes screen and keyboard, but does not
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// reset VIC-II. See here: https://csdb.dk/forums/index.php?roomid=11&topicid=17048&firstpost=22
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// This is a part CINT which initializes screen and keyboard
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//
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// For more details see:
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// - [RG64] C64 Programmer's Reference Guide - page 280
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// - [CM64] Compute's Mapping the Commodore 64 - page 242
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cint_screen_keyboard_real:
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// XXX check what really is performed here
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// According to [CM64], this routine checks for PAL/NTSC. It's definitely not done
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// within the 'BRK' part, this can be easily checked - POKE something
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// to address 678 on a real C64, press STOP+RESTORE, the value won't change
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// Detect video system (PAL/NTSC), use Graham's method, as it's short and reliable
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// see here: https://codebase64.org/doku.php?id=base:detect_pal_ntsc
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lda #$C8 // preparation, as the VIC might be uninitialized
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sta VIC_SCROLX
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cint_w0:
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lda VIC_RASTER
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cint_w1:
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cmp VIC_RASTER
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beq cint_w1
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bmi cint_w0
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// Result in A, if no interrupt happened during the test:
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// #$37 -> 312 rasterlines, PAL, VIC 6569
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// #$06 -> 263 rasterlines, NTSC, VIC 6567R8
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// #$05 -> 262 rasterlines, NTSC, VIC 6567R56A
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cmp #$07
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bcs cint_pal
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cint_ntsc:
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// NTSC C64 (https://codebase64.org/doku.php?id=base:cpu_clocking),
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// is clocked at 1.022727 MHz, so that 1/60s is 17045 CPU cycles
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ldy #<17045
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ldx #>17045
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sty CIA1_TIMALO
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stx CIA1_TIMAHI
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lda #$00
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beq !+
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cint_pal:
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lda #$01
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!:
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sta TVSFLG
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cint_brk: // entry for BRK and STOP+RESTORE - XXX, where should it start?
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cint_screen_keyboard:
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// Setup KEYLOG vector
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@@ -0,0 +1,22 @@
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//
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// Part of the official Kernal routine, described in:
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//
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// - [RG64] C64 Programmer's Reference Guide - page 280
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// - [CM64] Compute's Mapping the Commodore 64 - page 242
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//
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// CPU registers that has to be preserved (see [RG64]): none
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//
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cint_legacy: // $E518
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// Setup video and I/O
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// See here: https://csdb.dk/forums/index.php?roomid=11&topicid=17048&firstpost=22
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jsr setup_vicii
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// Code below must be placed under $E51B, or some code will break - see here:
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// - https://csdb.dk/forums/index.php?roomid=11&topicid=17048&firstpost=2
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// Game 'Operacja Proboszcz' is one example.
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jmp cint_screen_keyboard // XXX try to fit the code here
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@@ -0,0 +1,3 @@
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Game 'Operacja Proboszcz' explicitly calls $E51B - thus, it is sane
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to place old CINT routine in it's original place
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@@ -1,6 +0,0 @@
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// Routine too long to fit here
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cint_screen_keyboard:
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jmp cint_screen_keyboard_real
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@@ -1,2 +0,0 @@
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Game 'Operacja Proboszcz' explicitly calls this location.
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@@ -77,17 +77,16 @@ IOINIT:
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// Set timer interval to ~1/60th of a second
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// (This value was calculated by running a custom IRQ handler on a C64
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// with original KERNAL, and writing the values of $DC04/5 to the screen
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// in the IRQ handler to see roughly what value the timers must be set to)
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// ldy #<16380
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// ldx #>16380
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// Probably NTSC is the default one, as PAL support was introduced later,
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// in a patch - see [CM64] page 242 and page:
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// - http://commodore64.se/wiki/index.php/Commodore_64_KERNAL_ROM_versions
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// "The KERNAL ROM R1 was obviously used only in early NTSC systems. It lacks the PAL/NTSC detection"
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// PAL C64 (https://codebase64.org/doku.php?id=base:cpu_clocking),
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// is clocked at 0.985248 MHz, so that 1/60s is 16421 CPU cycles
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// NTSC C64 (https://codebase64.org/doku.php?id=base:cpu_clocking),
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// is clocked at 1.022727 MHz, so that 1/60s is 17045 CPU cycles
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ldy #<16421
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ldx #>16421
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ldy #<17045
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ldx #>17045
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sty CIA1_TIMALO
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stx CIA1_TIMAHI
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@@ -10,7 +10,47 @@
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CINT:
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// Setup video and I/O
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jsr setup_vicii
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jsr cint_legacy
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jmp cint_screen_keyboard
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cint_check_pal_ntsc:
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// Detect video system (PAL/NTSC), use Graham's method, as it's short and reliable
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// see here: https://codebase64.org/doku.php?id=base:detect_pal_ntsc
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lda VIC_RASTER
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!:
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cmp VIC_RASTER
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beq !-
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bmi cint_check_pal_ntsc
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// Result in A, if no interrupt happened during the test:
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// #$37 -> 312 rasterlines, PAL, VIC 6569
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// #$06 -> 263 rasterlines, NTSC, VIC 6567R8
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// #$05 -> 262 rasterlines, NTSC, VIC 6567R56A
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cmp #$07
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bcc cont_done
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cint_pal:
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// (This value was calculated by running a custom IRQ handler on a C64
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// with original KERNAL, and writing the values of $DC04/5 to the screen
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// in the IRQ handler to see roughly what value the timers must be set to)
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// ldy #<16380
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// ldx #>16380
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// PAL C64 (https://codebase64.org/doku.php?id=base:cpu_clocking),
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// is clocked at 0.985248 MHz, so that 1/60s is 16421 CPU cycles
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ldy #<16421
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ldx #>16421
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sty CIA1_TIMALO
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stx CIA1_TIMAHI
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lda #$01
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!:
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sta TVSFLG
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cont_done:
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rts
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@@ -12,8 +12,12 @@ default_brk_handler:
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jsr JRESTOR
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jsr JIOINIT
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jsr setup_vicii // XXX should probably be a part of cint_brk
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jsr cint_brk
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// Original routine calls just a part of CINT - but I'm not sure which one. Most likely it
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// skips the PAL/NTSC check by calling $E518. I suspect bug in the original ROM, let's
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// call the whole CINT, just to be sure everything is initialized.
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jsr CINT
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cli
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