56 lines
1.5 KiB
C
56 lines
1.5 KiB
C
/**
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* ops/eq.c
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*
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* Post Scarcity Software Environment: eq.
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*
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* Test for pointer equality.
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*
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* (c) 2026 Simon Brooke <simon@journeyman.cc>
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* Licensed under GPL version 2.0, or, at your option, any later version.
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*/
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#include "memory/memory.h"
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#include "memory/pointer.h"
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#include "memory/stack.h"
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/**
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* @brief Function; do these two pointers point to the same object?
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*
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* Shallow, cheap equality.
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*
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* TODO: if either of these pointers points to a cache cell, then what
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* we need to check is the cached value, which is not so cheap. Ouch!
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*
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* @param a a pointer;
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* @param b another pointer;
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* @return `true` if they are the same, else `false`
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*/
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bool eq( struct pso_pointer a, struct pso_pointer b ) {
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return ( a.node == b.node && a.page == b.page && a.offset == b.offset );
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}
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/**
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* Function; do all arguments to this finction point to the same object?
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*
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* Shallow, cheap equality.
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*
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* * (eq? args...)
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*
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* @param frame my stack_frame.
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* @param frame_pointer a pointer to my stack_frame.
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* @param env my environment (ignored).
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* @return `t` if all args are pointers to the same object, else `nil`;
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*/
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struct pso_pointer lisp_eq( struct stack_frame *frame,
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struct pso_pointer frame_pointer,
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struct pso_pointer env ) {
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struct pso_pointer result = t;
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if ( frame->args > 1 ) {
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for ( int b = 1; ( truep( result ) ) && ( b < frame->args ); b++ ) {
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result = eq( frame->arg[0], fetch_arg( frame, b ) ) ? t : nil;
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}
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}
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return result;
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}
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