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use the proper term for this (memoizing)

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Connor Olding 2016-10-14 03:34:00 -07:00
parent ef07b5b18e
commit dfd925e70f
1 changed files with 7 additions and 6 deletions
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13
example.asm
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@ -5,7 +5,7 @@
[max_n]: 47 [max_n]: 47
fib: fib:
; calculate the nth fibonacci number, caching results 1 to 47 to a table ; calculate the nth fibonacci number, memoizing results 1 to 47 in a table.
; only valid for values of n between 0 and 47 inclusive. ; only valid for values of n between 0 and 47 inclusive.
; a0: n ; a0: n
; v0: Fn ; v0: Fn
@ -35,9 +35,10 @@ fib:
; load the value from the look-up table. ; load the value from the look-up table.
; pseudo-instruction utilizing addressing modes: ; pseudo-instruction utilizing addressing modes:
lw t9, fib_cache(t0) lw t9, fib_memo(t0)
; branch to return the look-up value if it's non-zero, meaning it has been cached. ; branch to return the look-up value if it's non-zero,
; meaning it has been memoized.
bnez t9, + bnez t9, +
; once again, note that this is the delay slot of the branch instruction. ; once again, note that this is the delay slot of the branch instruction.
@ -72,9 +73,9 @@ fib:
; loop finished, copy the result to return. ; loop finished, copy the result to return.
mov v0, t1 mov v0, t1
; cache the result for next time. ; memoize the result for next time.
; pseudo-instruction not unlike the previous lw: ; pseudo-instruction not unlike the previous lw:
sw v0, fib_cache(t0) sw v0, fib_memo(t0)
; here's the + label used at the start of the routine. ; here's the + label used at the start of the routine.
+: +:
@ -89,7 +90,7 @@ fib:
nop nop
; set up initial values in the look-up table. ; set up initial values in the look-up table.
fib_cache: fib_memo:
; lips doesn't yet have a way to specify "x, n times", ; lips doesn't yet have a way to specify "x, n times",
; so this will do for now. ; so this will do for now.
.word 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 .word 0, 0, 0, 0, 0, 0, 0, 0, 0, 0