Fix StackFrameCreate when the base stack pointer is larger than the max positive signed 16-bit integer (I7-2382)#188
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Building stories with a significant (but not excessive) number of objects (e.g. long tables) may lead to an I7SFRAME value that overflows the signed 16-bit signed maximum positive value, even though the pointer itself would still be valid. When this happens, the subsequent signed check in StackFrameCreate would lead to a memory allocation failure on the first stack frame creation even if it was a 0 byte allocation. Using an unsigned comparison avoids this issue. A similar fix was proposed for an older version of Inform7 in this thread over at IF forum: https://intfiction.org/t/memory-allocation-error-z-code-vs-blank-story-tab-glulx/60213/23 In my proposed patch, there is an additional check to prevent the proposed new pointer from ever becoming “truly” negative by making sure that the byte size WORDSIZE*size is not larger than I7SFRAME. Note that this patch APPARENTLY breaks test Chapter7-G, but looking at the history of this test, it appears that in commit 61534b3 (Reform of pointer-value kind support and Neptune) a significant fraction of the original log was replaced by a MemoryAllocationFailed error. I posit that this commit is fixing an issue introduced by that commit. A restoration of the original expected output will be included in a later change.
As discussed in the previous commit, this had gotten clobbered in commit 61534b3 Only one change is introduced compared to the original log: the implicit action (Jim first taking the pyramid of empty beer bottles) is removed because the pyramid of empty beer bottles is fixed and cannot be taken.
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Fix an issue related to the use of signed comparison in StackFrameCreate, and restore a test case whose reference log had gotten mangled in some previous commit due to a related error message. The details are in the first commit.