AnachronautandClaude Opus 5
3449405b18
CosmOS had 1,161 bytes of Program Memory left before the address applications load at, and Tab completion is not going to fit in that with anything to spare. So the wall moves up one page: the system keeps below 0x4FFF and 0x2FFF, and an application is based at 0x5000 and 0x3000. A PAGE IS A CHEAP THING TO GIVE IT AND AN EXPENSIVE THING TO RUN OUT OF. An application still has 44K of Program Memory before the vector table and the largest one here uses 7.5K, so what was taken from applications is space nothing has ever asked for - while what the system gained is the difference between building the next thing and counting bytes while building it. Not doubling, which was the version that would have cost application space worth minding. One page, and the same again when it is needed. Nothing in the machine knows where the wall is, so this is 34 #Base lines, one threshold in the fault handler, and the table in the CosmOS README that Tests/docs.sh reads its limits out of. The native assembler's scratch map had to move with it, and docs.sh said so before anything ran: its data reached 0x40D6 and its buffers began at 0x4000, so they were sitting on its variables. That file already carries a paragraph about the floor coming up and the map staying where it was. It has happened twice now, and been caught by a check the first time wrote. Twenty three recordings are the same runs a page higher. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW
76 lines
3.3 KiB
NASM
76 lines
3.3 KiB
NASM
; This is an implementation of The Sieve of Eratosthenes that finds all the primes between 2 and 255.
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#Include services.asm
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#Program
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#Base 0x5000
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start:
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; Search the list until we find a prime.
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SETD DataTop
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CCF ; Clear the carry flag. In later cycles, the carry flag will be set at the end of the next loop. We'll want it cleared.
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RSTA
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RSTB
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findPrimeLoop:
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LDB ; Load an element into B.
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BRB foundPrime ; If it's zero, it's a prime.
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INCA ; Increment A, our index.
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INCD ; Increment the Data Pointer.
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BRA end ; If A becomes zero, we've looked through the whole list without finding another prime.
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BRI findPrimeLoop ; Keep searching for the next prime.
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foundPrime:
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; If we've found a prime, we should print it and mark it off the list so we don't print it again.
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CALL printByteDecimal ; A contains our prime, so we can just call the print subroutine.
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CALL blankSpace ; Put a space afterward to keep things easy to read.
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INIB 0x01 ; Set B to 1.
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STB ; Mark this prime off the list.
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markMultiples:
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; Now, we mark each multiple of this prime as nonprime until we reach the end of the list.
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PSHD ; Save the Data Pointer to the stack.
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POPB ; Pop its low byte into B.
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ADD ; Add them together.
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PSHQ ; Store the result back onto the stack.
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POPD ; Pop the modified address into the Data Pointer.
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INIB 0x01 ; Set B to 1.
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STB ; Store B to mark the value as nonprime.
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BRC start ; If the previous add overflowed, the next nonprime is outside the range of our list, so start over with a new prime.
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BRI markMultiples ; Otherwise, loop again to mark the next multiple as nonprime.
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end:
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CALL lineFeed ; Print a linefeed to make it look nice.
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RSTA
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SWI osExit ; The program is done, we found all the primes!
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#Data
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#Base 0x3000
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; The table of our prime candidates. It has to begin on a page boundary: marking walks
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; the pointer's low byte and treats the carry out as running off the end of the table,
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; which only finds the right end if the table starts on one.
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#Align 0x100
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DataTop:
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0x01 0x01 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
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0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
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0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
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0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
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0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
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0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
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0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
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0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
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0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
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0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
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0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
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0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
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0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
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0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
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0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
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0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
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#Include print.asm
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