diff options
Diffstat (limited to 'programs/sub-suite/tmp-stuff/test-size.s')
| -rw-r--r-- | programs/sub-suite/tmp-stuff/test-size.s | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/programs/sub-suite/tmp-stuff/test-size.s b/programs/sub-suite/tmp-stuff/test-size.s new file mode 100644 index 0000000..b543a36 --- /dev/null +++ b/programs/sub-suite/tmp-stuff/test-size.s @@ -0,0 +1,59 @@ +MAGIC = $AA + + +.org 0 +findramend: + and #0 ; Reset A. +; lda #MAGIC ; Set A to a magic number. +@loop: + mov a, (d) ; Preserve the value. + mov (d), #MAGIC ; Write the magic number to the current end of RAM. + cmp (d), #MAGIC ; Is the value in RAM, the same as the magic number we wrote? + bne @moveback ; No, so move back until we find the last writable memory location. + mov (d), a ; Yes, so restore the previous value. + add.w d, #$4000 ; Increment the end of RAM pointer by 16K. + bra @loop ; Keep looping. +@moveback: + dec d ; Decrement the end of RAM pointer. + mov a, (d) ; Preserve the value. + mov (d), #MAGIC ; Write the magic number to the current end of RAM. + cmp (d), #MAGIC ; Is the value in RAM, the same as the magic number we wrote? + bne @moveback ; No, so keep looping. + mov (d), a ; Yes, so restore the previous value. +@end: + mov a, d ; Return the end of RAM pointer. +; ple.q ; Restore E. + rts ; End of findramend. + + +;findramend: +; phe.q ; Preserve E. +; phb.q ; Preserve B. +; mov e, d ; Set E to the RAM pointer. +; and #0 ; Reset A. +; lda #MAGIC ; Set A to a magic number. +;@loop: +; ldb (e) ; Preserve the value. +; sta (e) ; Write the magic number to the current end of RAM. +; cmp (e) ; Is the value in RAM, the same as the magic number we wrote? +; bne @moveback ; No, so move back until we find the last writable memory location. +; stb (e) ; Yes, so restore the previous value. +; ade.w #$4000 ; Increment the end of RAM pointer by 16K. +; bra @loop ; Keep looping. +;@moveback: +; dee ; Decrement the end of RAM pointer. +; ldb (e) ; Preserve the value. +; sta (e) ; Write the magic number to the current end of RAM. +; cmp (e) ; Is the value in RAM, the same as the magic number we wrote? +; bne @moveback ; No, so keep looping. +; stb (e) ; Yes, so restore the previous value. +;@end: +; mov a, e ; Return the end of RAM pointer. +; ple.q ; Restore E. +; plb.q ; Restore B. +; rts ; End of findramend. + +a +.org findramend +v +q |