Added a fast subroutine to multiply two signed 8-bit numbers.

2014-05-11 01:08:27 -04:00
parent 63b5f75a7f
commit 228b9d1718
2 changed files with 97 additions and 0 deletions
--- a/libsrc/common/cc65_imul8x8r16.s
+++ b/libsrc/common/cc65_imul8x8r16.s
@@ -0,0 +1,22 @@
+;
+; 2014-03-27, Oliver Schmidt
+; 2014-05-08, Greg King
+;
+; CC65 library: 8x8 => 16 signed multiplication
+;
+
+        .export         _cc65_imul8x8r16
+        .import         imul8x8r16, popa, ptr1:zp
+
+
+;---------------------------------------------------------------------------
+; 8x8 => 16 signed multiplication routine.
+
+
+.proc   _cc65_imul8x8r16
+
+        sta     ptr1
+        jsr     popa
+        jmp     imul8x8r16
+
+.endproc