shithub: sl

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ref: c2b864c7185a983b3ec16f7e38332a6518521e30
parent: ce2bd9c0913fdc7127a52bcb91ffb9d9d03c6c5c
author: Sigrid Solveig Haflínudóttir <sigrid@ftrv.se>
date: Mon Feb 24 19:45:55 EST 2025 

reduce branching and FL(...) reads a bit


--- a/src/flisp.c
+++ b/src/flisp.c
@@ -554,8 +554,8 @@
 static value_t
 _applyn(int n)
 {
-	value_t f = FL(sp)[-n-1];
 	value_t *saveSP = FL(sp);
+	value_t f = saveSP[-n-1];
 	value_t v;
 	if(iscbuiltin(f))
 		v = ((cvalue_t*)ptr(f))->cbuiltin(saveSP-n, n);
@@ -676,8 +676,10 @@
 
 fl_hotfn
 static value_t
-list(value_t *args, int nargs, int star)
+list(value_t *args, int nargs, bool star)
 {
+	if(fl_unlikely(nargs == 0))
+		return FL_nil;
 	value_t v = cons_reserve(nargs);
 	cons_t *c = ptr(v);
 	for(int i = 0; i < nargs; i++){
@@ -697,10 +699,10 @@
 {
 	if(!iscons(L))
 		return FL_nil;
+	value_t *plcons = FL(sp);
+	value_t *pL = plcons+1;
 	PUSH(FL_nil);
 	PUSH(L);
-	value_t *plcons = FL(sp)-2;
-	value_t *pL = FL(sp)-1;
 	value_t c;
 	c = mk_cons(); PUSH(c);  // save first cons
 	car_(c) = car_(*pL);
@@ -725,8 +727,8 @@
 {
 	value_t *saveSP = FL(sp);
 	value_t v = FL_nil;
-	value_t thunk = FL(sp)[-2];
-	FL(sp)[-2] = FL(sp)[-1];
+	value_t thunk = saveSP[-2];
+	FL(sp)[-2] = saveSP[-1];
 	FL(sp)[-1] = thunk;
 
 	FL_TRY{
@@ -1059,7 +1061,7 @@
 		return args[0];
 	if(nargs == 0)
 		argcount(nargs, 1);
-	return list(args, nargs, 1);
+	return list(args, nargs, true);
 }
 
 BUILTIN("stacktrace", stacktrace)
--- a/src/vm.inc
+++ b/src/vm.inc
@@ -287,7 +287,6 @@
 	if(FL(curheap) > FL(lim)){
 		FL(sp) = sp;
 		fl_gc(0);
-		sp = FL(sp);
 	}
 	cons_t *c = (cons_t*)FL(curheap);
 	FL(curheap) += sizeof(cons_t);
@@ -337,7 +336,7 @@
 	}
 	fixnum_t s = (fixnum_t)nargs - (fixnum_t)i;
 	if(s > 0){
-		value_t v = list(bp+i, s, 0);
+		value_t v = list(bp+i, s, false);
 		bp[i] = v;
 		if(s > 1){
 			bp[i+1] = bp[nargs+0];
@@ -645,12 +644,8 @@
 	n = *ip++;
 LABEL(apply_list):;
 	value_t v;
-	if(n > 0){
-		v = list(sp-n, n, 0);
-		sp -= n;
-	}else{
-		v = FL_nil;
-	}
+	v = list(sp-n, n, false);
+	sp -= n;
 	*sp++ = v;
 	NEXT_OP;
 }
@@ -807,10 +802,8 @@
 LABEL(apply_vector):;
 	FL(sp) = sp;
 	value_t v = alloc_vector(n, 0);
-	if(n){
-		memcpy(&vector_elt(v, 0), sp-n, n*sizeof(value_t));
-		sp -= n;
-	}
+	memcpy(&vector_elt(v, 0), sp-n, n*sizeof(value_t));
+	sp -= n;
 	*sp++ = v;
 	NEXT_OP;
 }