Thanks Eliot. Your linked article clears it up: http://www.mirandabanda.org/cogblog/2008/07/22/closures-part-ii-the-bytecodes/
140 10001100 kkkkkkkk jjjjjjjj Push Temp At kkkkkkkk In Temp Vector At: jjjjjjjj
This fetches the local at offset j..j on the stack and push the k..k’th element in it.
The next two store into the k..k’th element of the local at j..j, one
version popping the result off the stack. This is a general convention
in the Smalltalk-80 compiler. These are store and store-pop forms of
almost every store opcode. The store form is used in the stores into
vat and vax in things like
var := vat := vax := expr
whereas the pop form gets used in the store into var.
141 10001101 kkkkkkkk jjjjjjjj Store Temp At kkkkkkkk In Temp Vector At: jjjjjjjj
142 10001110 kkkkkkkk jjjjjjjj Pop and Store Temp At kkkkkkkk In Temp Vector At: jjjjjjjj
The final bytecode is more interesting.
The wording is unclear to me: "This fetches the local at offset j..j on the stack and push the k..k’th element in it."
Does it mean, get local at index j..j and push onto the stack the k..k'th element in it?
So
109 <8C 00 01> pushTemp: 0 inVectorAt: 1
Get temp at 1 (j..j) and push element at 0 (k..k) ??
97 <8E 00 01> popIntoTemp: 0 inVectorAt: 1
get vector at temp index 1 (j..j) and pop and store stack value into element 0 (k..k) ??
116 <8D 00 01> storeIntoTemp: 0 inVectorAt: 1
I dont understand this one, store what? into element 0 of vector at 1 ??
In the pop variation I can understand where the value is coming from, but not the above
form. Please can you clarify?
Rgs, James.
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