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restore [o|i]ip zeroing to trust and fix '$get_clause_p'/3 (#2238)

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Mark
2023-12-20 20:45:11 -07:00
parent 44a61fa72c
commit 46e432c4d9
5 changed files with 86 additions and 75 deletions
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23
src/machine/mod.rs
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@@ -1010,6 +1010,20 @@ impl Machine {
self.machine_st.heap.truncate(target_h);
// these registers don't need to be reset here and MUST
// NOT be (nor in indexed_try! trust_epilogue is an
// exception, see next paragraph)! oip could be reset
// without any adverse effects but iip is needed by
// get_clause_p to find the last executed clause/2 clause.
// trust_epilogue must reset these for the sake of
// subsequent predicates beginning with
// switch_to_term. get_clause_p copes by checking
// self.machine_st.b > self.machine.e: if true, it is safe
// to use self.machine_st.iip; if false, use the choice
// point left at the top of the stack by '$clause'
// (specifically its biip value).
// self.machine_st.oip = 0;
// self.machine_st.iip = 0;
} else {
@@ -1059,13 +1073,8 @@ impl Machine {
self.machine_st.stack.truncate(b);
self.machine_st.heap.truncate(target_h);
// these registers don't need to be reset here and MUST NOT be
// (nor in indexed_try to trust_epilogue)! oip could be reset
// without any adverse effects but iip is needed by
// get_clause_p to find the last executed clause/2 clause.
// self.machine_st.oip = 0;
// self.machine_st.iip = 0;
self.machine_st.oip = 0;
self.machine_st.iip = 0;
}
#[inline(always)]