forth-riscv

commit b5cd66c29256d3ab4ed670ecb321ac93a67d6902
parent 6b5863463084e563b626da50f4ea7a9aff0edb95
Author: Christian Ermann <christianermann@gmail.com>
Date:   Wed,  4 Dec 2024 11:04:38 -0800

Refactor 'hash'

Diffstat:
M
src/forth.s
 | 
28
++++++++++++----------------

1 file changed, 12 insertions(+), 16 deletions(-)
diff --git a/src/forth.s b/src/forth.s
@@ -1398,26 +1398,22 @@ defword "create", create, 0x26BB595D, flags=flag_immediate
     jal l_bracket
     exit
 
-defcode "hash", hash, 0xEDBF0FE3
-    mv x, w
-    pop w
-    push_ret ra
-    jal hash_impl
-    pop_ret ra
-    next
-
-hash_impl: # 32-bit fnv1a
+defcode "hash", hash, 0xEDBF0FE3 # 32-bit fnv1a
+    # ( addr len -- hash )
+    pop x
     li t0, 2166136261 # hash
     li t1, 16777619   # prime
-_hash_char:
-    lb t2, 0(w)
-    addi w, w,  1
-    addi x, x, -1
-    xor t0, t0, t2
+    blez w, _hash_done
+_hash_loop:
+    lb y, 0(x)
+    addi x, x, 1
+    addi w, w, -1
+    xor t0, t0, y
     mul t0, t0, t1
-    bgtz x, _hash_char
+    bgtz w, _hash_loop
+_hash_done:
     mv w, t0
-    ret
+    next
 
 defword "[", l_bracket, 0xDE0C1FBA, flags=flag_immediate
     # set state