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# Helper to check an array's bounds, and to abort if they're violated.
# Really only intended to be called from code generated by mu.subx.

== code

__check-mu-array-bounds:  # index: int, elem-size: int, arr-size: int, function-name: (addr array byte), array-name: (addr array byte)
    # . prologue
    55/push-ebp
    89/<- %ebp 4/r32/esp
    # . save registers
    50/push-eax
    51/push-ecx
    52/push-edx
    # . not bothering saving ebx; it's only clobbered if we're going to abort
    # ecx = arr-size
    8b/-> *(ebp+0x10) 1/r32/ecx
    # var overflow/edx: int = 0
    ba/copy-to-edx 0/imm32
    # var offset/eax: int = index * elem-size
    8b/-> *(ebp+8) 0/r32/eax
    f7 4/subop/multiply-eax-with *(ebp+0xc)
    # check for overflow
    81 7/subop/compare %edx 0/imm32
    0f 85/jump-if-!= __check-mu-array-bounds:overflow/disp32
    # check bounds
    39/compare %eax 1/r32/ecx
    0f 82/jump-if-unsigned< $__check-mu-array-bounds:end/disp32  # negative index should always abort
    # abort if necessary
    (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "fn " 3 0)  # 3=cyan
    (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 *(ebp+0x14) 3 0)  # 3=cyan
    (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 ": offset " 3 0)  # 3=cyan
    (draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0 %eax 3 0)  # 3=cyan
    (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 " is too large for array '" 3 0)  # 3=cyan
    (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 *(ebp+0x18) 3 0)  # 3=cyan
    (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "'" 3 0)  # 3=cyan
    (abort "")
    # never gets here
$__check-mu-array-bounds:end:
    # . restore registers
    5a/pop-to-edx
    59/pop-to-ecx
    58/pop-to-eax
    # . epilogue
    89/<- %esp 5/r32/ebp
    5d/pop-to-ebp
    c3/return

__check-mu-array-bounds:overflow:
    (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "fn " 3 0)  # 3=cyan
    (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 *(ebp+0x14) 3 0)  # 3=cyan
    (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 ": offset to array '" 3 0)  # 3=cyan
    (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 *(ebp+0x18) 3 0)  # 3=cyan
    (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "' overflowed 32 bits" 3 0)  # 3=cyan
    (abort "")
    # never gets here

__mu-abort-null-index-base-address:
    (abort "null address in 'index'")

__mu-abort-null-get-base-address:
    (abort "null address in 'get'")
w"> ingredients to new-array] *result <- put-index *result, i, curr-value i <- add i, 1 loop } return result ] # fill an existing array with a set of numbers # (contributed by Caleb Couch) def fill array:&:@:num -> array:&:@:num [ local-scope load-ingredients loopn:num <- copy 0 length:num <- length *array { length?:bool <- equal loopn, length break-if length? object:num, arg-received?:bool <- next-ingredient break-unless arg-received? *array <- put-index *array, loopn, object loopn <- add loopn, 1 loop } ] scenario fill-on-an-empty-array [ local-scope array:&:@:num <- new number:type, 3 run [ array <- fill array, 1 2 3 10:@:num/raw <- copy *array ] memory-should-contain [ 10 <- 3 11 <- 1 12 <- 2 13 <- 3 ] ] scenario fill-overwrites-existing-values [ local-scope array:&:@:num <- new number:type, 3 *array <- put-index *array, 0, 4 run [ array <- fill array, 1 2 3 10:@:num/raw <- copy *array ] memory-should-contain [ 10 <- 3 11 <- 1 12 <- 2 13 <- 3 ] ] scenario fill-exits-gracefully-when-given-no-ingredients [ local-scope array:&:@:num <- new number:type, 3 run [ array <- fill array 10:@:num/raw <- copy *array ] memory-should-contain [ 10 <- 3 11 <- 0 12 <- 0 13 <- 0 ] ] # swap two elements of an array # (contributed by Caleb Couch) def swap array:&:@:num, index1:num, index2:num -> array:&:@:num [ local-scope load-ingredients object1:num <- index *array, index1 object2:num <- index *array, index2 *array <- put-index *array, index1, object2 *array <- put-index *array, index2, object1 ] scenario swap-works [ local-scope array:&:@:num <- new number:type, 4 array <- fill array, 4 3 2 1 run [ array <- swap array, 0, 2 10:num/raw <- index *array, 0 11:num/raw <- index *array, 2 ] memory-should-contain [ 10 <- 2 11 <- 4 ] ] # reverse the elements of an array # (contributed by Caleb Couch) def reverse array:&:@:_elem -> array:&:@:_elem [ local-scope load-ingredients start:num <- copy 0 length:num <- length *array end:num <- subtract length, 1 { done?:bool <- greater-or-equal start, end break-if done? array <- swap array, start, end start <- add start, 1 end <- subtract end, 1 loop } ] scenario reverse-array-odd-length [ local-scope array:&:@:num <- new number:type, 3 array <- fill array, 3 2 1 run [ array <- reverse array 10:@:num/raw <- copy *array ] memory-should-contain [ 10 <- 3 11 <- 1 12 <- 2 13 <- 3 ] ] scenario reverse-array-even-length [ local-scope array:&:@:num <- new number:type, 4 array <- fill array, 4 3 2 1 run [ array <- reverse array 10:@:num/raw <- copy *array ] memory-should-contain [ 10 <- 4 11 <- 1 12 <- 2 13 <- 3 14 <- 4 ] ]