Files
SplitBit-Emulator/Programs/Examples/gameOfLife/16x16LifeModern.asm
T
AnachronautandClaude Opus 5 43a05b3df1 Replace the escape parser with cursor registers
The console had grown an ANSI parser, and that was the wrong shape. ANSI exists because a
screen used to be on the other end of a serial line and a byte stream was the only channel
there was. This screen is memory the program can already address, so reaching it by sending
characters for a state machine to take apart is a middleman for something the machine does
better - and it meant accepting an open protocol somebody else defines, in hardware, with no
natural end to it. Everything else on this machine is registers.

So the console gets three: cursor row at 0x03, cursor column at 0x04, and a command port at
0x05 where 1 clears the screen. Both cursor registers are READ as well as written, which is
the thing an escape cannot do without sending a query and parsing a reply - a routine that
wants to put the cursor back where it found it can now ask.

Clearing is one command against a thousand cells walked one at a time. Snake and Life are
smaller for it: 2,168 bytes to 2,163 and 1,410 to 1,396.

A HOST TERMINAL STILL SPEAKS ANSI, and bridging to the host is the emulator's job, the same
job it does reading standard input. So the escapes are now GENERATED, outbound, for the set
this device chooses, rather than parsed inbound as though the machine were a terminal. The
set cannot grow behind our backs because we are the ones saying it. The cursor is announced
lazily, at the next character rather than at the register write, so setting a row and a
column costs one sequence rather than two.

The console's block widens from three ports to six, which registryTest noticed: it had been
asking about port 0x05 precisely BECAUSE nothing was there, and the console had just moved
in. Re-blessing it would have left it checking nothing, so it asks about 0x80 instead -
clear of the console, the disk, the screen, the controller, and the sound device coming to
0x40.

Six checks in Tests/video.sh swapped from the sequences to the registers, including that the
cursor reads back and that one sent past the edge is clamped rather than refusing. Those
checks also stopped counting bytes from the ends of a file, which had quietly started
measuring an escape the moment the console began announcing the cursor.

SplitLint caught the one thing worth catching in the port: the clear command leaves A at 1
and key mode is also 1, so the second load looks redundant. Acting on it would tie a console
command to a console mode by coincidence, and break silently if either ever moved, so it is
suppressed with that reason rather than removed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW
2026-08-28 23:08:52 -04:00

262 lines
3.4 KiB
NASM

; Conway's Game of Life rewritten for SplitBit's four-Data-Pointer ISA.
;
; The representation and display match 16x16Life.asm: a visible 16x16 field,
; a dead border, and interleaved current/next bytes. DP0 walks the board, DP1
; and DP2 address the loop counters, and volatile DP3 walks the neighborhood.
#Include print.asm
#Program
start:
CALL seedGlider
INIA 0x01
OUTA 0x05 ; Console command: clear the screen
generationLoop:
CALL renderBoard
CALL evolveBoard
CALL commitBoard
CALL frameDelay
BRI generationLoop
seedGlider:
SETD.0 Board
DPUP.0 0d42
INIA 0x01
STA.0
SETD.0 Board
DPUP.0 0d80
STA.0
SETD.0 Board
DPUP.0 0d112
STA.0
DPUP.0 0d02
STA.0
DPUP.0 0d02
STA.0
RET
renderBoard:
RSTA
OUTA 0x03
OUTA 0x04 ; Cursor to row 0, column 0
SETD.1 RowCount
SETD.2 ColCount
INIA 0d16
STA.1
SETD.0 Board
DPUP.0 0d38
renderRow:
INIA 0d16
STA.2
renderCell:
LDA.0
BRA renderDead
INIB 0x23
OUTB 0x00
BRI renderCellDone
renderDead:
INIB 0x20
OUTB 0x00
renderCellDone:
DPUP.0 0d02
LDA.2
DECA
STA.2
BRA renderRowDone
BRI renderCell
renderRowDone:
CALL lineFeed
DPUP.0 0d04
LDA.1
DECA
STA.1
BRA renderDone
BRI renderRow
renderDone:
RET
evolveBoard:
SETD.1 RowCount
SETD.2 ColCount
INIA 0d16
STA.1
SETD.0 Board
DPUP.0 0d38
evolveRow:
INIA 0d16
STA.2
evolveCellLoop:
CALL evolveCell
DPUP.0 0d02
LDA.2
DECA
STA.2
BRA evolveRowDone
BRI evolveCellLoop
evolveRowDone:
DPUP.0 0d04
LDA.1
DECA
STA.1
BRA evolveDone
BRI evolveRow
evolveDone:
RET
evolveCell:
CALL countNeighbors
MVQB ; B is the neighbor count from here down.
; Three neighbors always produces a live cell.
INIA 0d03
CCF
SUB
BRQ makeAlive
; Two neighbors preserve the current state.
INIA 0d02
CCF
SUB
BRQ preserveCell
makeDead:
RSTA
INCD.0
STA.0
DECD.0
RET
preserveCell:
LDA.0
BRA makeDead
makeAlive:
INIA 0x01
INCD.0
STA.0
DECD.0
RET
; Return the eight-neighbor sum in Q. One Stack round-trip copies DP0 into
; volatile DP3; MVQA then keeps the running total entirely in registers.
countNeighbors:
PSHD.0
POPD.3
RSTA
DPDN.3 0d38
LDB.3
CCF
ADD
MVQA
DPUP.3 0d02
LDB.3
CCF
ADD
MVQA
DPUP.3 0d02
LDB.3
CCF
ADD
MVQA
DPUP.3 0d32
LDB.3
CCF
ADD
MVQA
DPUP.3 0d04
LDB.3
CCF
ADD
MVQA
DPUP.3 0d32
LDB.3
CCF
ADD
MVQA
DPUP.3 0d02
LDB.3
CCF
ADD
MVQA
DPUP.3 0d02
LDB.3
CCF
ADD
RET
commitBoard:
SETD.1 RowCount
SETD.2 ColCount
INIA 0d18
STA.1
SETD.0 Board
commitRow:
INIA 0d18
STA.2
commitCell:
INCD.0
LDA.0
DECD.0
STA.0
DPUP.0 0d02
LDA.2
DECA
STA.2
BRA commitRowDone
BRI commitCell
commitRowDone:
LDA.1
DECA
STA.1
BRA commitDone
BRI commitRow
commitDone:
RET
frameDelay:
INIA 0xFF
delayOuter:
INIB 0xFF
delayInner:
DECB
BRB delayInnerDone
BRI delayInner
delayInnerDone:
DECA
BRA delayDone
BRI delayOuter
delayDone:
RET
#Data
RowCount:
0x00
ColCount:
0x00
; 18 by 18 cells with the current and next states interleaved, so 648 bytes. The
; original leaves this implicit and leans on Data Memory being zero, which works but
; means the assembler believes the board is one byte long: anything placed after it
; would land inside it, and nothing would say so. Reserving the region states how far
; it reaches, so a label added below here is safe.
Board:
#Reserve 0d648