diff options
Diffstat (limited to 'apps')
-rw-r--r-- | apps/advent2020/3a.mu | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/apps/advent2020/3a.mu b/apps/advent2020/3a.mu new file mode 100644 index 00000000..a2cc6fb6 --- /dev/null +++ b/apps/advent2020/3a.mu @@ -0,0 +1,110 @@ +# https://adventofcode.com/2020/day/3 +# +# To run (on Linux): +# $ git clone https://github.com/akkartik/mu +# $ cd mu +# $ ./translate_mu apps/advent2020/3a.mu +# $ ./a.elf < input +# +# You'll need to register to download the 'input' file for yourself. + +fn main -> _/ebx: int { + # represent trees in a 2D array of ints + # wasteful since each tree is just one bit + var trees-storage: (array int 0x2800) # 10k ints + var trees/esi: (addr array int) <- address trees-storage + var trees-length/ecx: int <- copy 0 + var num-rows: int + var width: int + # phase 1: parse each row of trees from stdin + { + var line-storage: (stream byte 0x40) # 64 bytes + var line/edx: (addr stream byte) <- address line-storage + { + # read line from stdin + clear-stream line + read-line-from-real-keyboard line + # if line is empty (not even a newline), quit + var done?/eax: boolean <- stream-empty? line + compare done?, 0 # false + break-if-!= + # wastefully recompute width on every line + # zero error-checking; we assume input lines are all equally long + copy-to width, 0 + # turn each byte into a tree and append it + $main:line-loop: { + var done?/eax: boolean <- stream-empty? line + compare done?, 0 # false + break-if-!= +#? print-int32-decimal 0, num-rows +#? print-string 0, " " +#? print-int32-decimal 0, width +#? print-string 0, "\n" + var dest/ebx: (addr int) <- index trees, trees-length + var c/eax: byte <- read-byte line + # newline comes only at end of line + compare c, 0xa # newline + break-if-= + # '#' = tree + compare c, 0x23 # '#' + { + break-if-!= + copy-to *dest, 1 + } + # anything else = no tree + { + break-if-= + copy-to *dest, 0 + } + increment width + trees-length <- increment + loop + } + increment num-rows + loop + } + } + # phase 2: compute + print-int32-decimal 0, num-rows + print-string 0, "x" + print-int32-decimal 0, width + print-string 0, "\n" + var i/eax: int <- copy 0 + { + compare i, num-rows + break-if->= + var j/ecx: int <- copy 0 + { + compare j, width + break-if->= +#? print-int32-decimal 0, i +#? print-string 0, " " +#? print-int32-decimal 0, j +#? print-string 0, "\n" + var src/eax: int <- index2d trees, i, j, width + print-int32-decimal 0, src +#? print-string 0, "\n" + j <- increment + loop + } + print-string 0, "\n" + i <- increment + loop + } + return 0 +} + +fn index2d _arr: (addr array int), _row: int, _col: int, width: int -> _/eax: int { + # handle repeating columns of trees + var dummy/eax: int <- copy 0 + var col/edx: int <- copy 0 + dummy, col <- integer-divide _col, width + # compute index + var index/eax: int <- copy _row + index <- multiply width + index <- add col + # look up array + var arr/esi: (addr array int) <- copy _arr + var src/eax: (addr int) <- index arr, index + return *src +} |