X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=device%2Flib%2Fz80%2Fmul.s;h=e81ac80040b958cb5be49d3e9b458f748d5900d7;hb=5a1d5e778e85664f4e6657019348b4756b16eacb;hp=00e6ce9ee2e9747a980aab13522a1c7a3d74b102;hpb=ca15c088b3c6d3cd14dee96ebbabe33a59d3c5af;p=fw%2Fsdcc

diff --git a/device/lib/z80/mul.s b/device/lib/z80/mul.s
index 00e6ce9e..e81ac800 100644
--- a/device/lib/z80/mul.s
+++ b/device/lib/z80/mul.s
@@ -1,101 +1,53 @@
-	;; Originally from GBDK by Pascal Felber.
-
-	.area	_CODE
-
-__mulschar_rrx_s::
-        ld      hl,#2
-        add     hl,sp
-
-        ld      e,(hl)
-        inc     hl
-        ld      l,(hl)
-
-        ;; Fall through
-__mulschar_rrx_hds::
-        ;; Need to sign extend before going in.
-        ld      c,l
-
-        ld      a,l
-        rla
-        sbc     a,a
-        ld      b,a
-
-        ld      a,e
-        rla
-        sbc     a,a
-        ld      d,a
-
-        jp      .mul16
-
-__muluchar_rrx_s::
-        ld      hl,#2
-        add     hl,sp
-
-        ld      e,(hl)
-
-        inc     hl
-        ld      c,(hl)
-
-        ;; Clear the top
-        xor     a
-        ld      d,a
-        ld      b,a
-
-        jp      .mul16
+        .area   _CODE
 
 __mulint_rrx_s::
-        ld      hl,#2
-        add     hl,sp
-
-        ld      e,(hl)
-        inc     hl
-        ld      d,(hl)
-        inc     hl
-        ld      a,(hl)
-        inc     hl
-        ld      h,(hl)
-        ld      l,a
+        pop     af
+        pop     hl
+        pop     de
+        push    de
+        push    hl
+        push    af
 
         ;; Fall through
 
 __muluchar_rrx_hds::
 __mulint_rrx_hds::
 	;; Parameters:
-	;;	HL, DE (left, right irrelivent)
+	;;	hl, de (left, right irrelevant)
 	ld	b,h
 	ld	c,l
 
 	;; 16-bit multiplication
 	;;
 	;; Entry conditions
-	;;   BC = multiplicand
-	;;   DE = multiplier
+	;; bc = multiplicand
+	;; de = multiplier
 	;;
 	;; Exit conditions
-	;;   DE = less significant word of product
+	;; hl = less significant word of product
 	;;
 	;; Register used: AF,BC,DE,HL
-.mul16:
-        ld      hl,#0
-        ld      a,b
-        ; ld c,c
-        ld      b,#16
+__mul16::
+	xor	a,a
+	ld	l,a
+	or	a,b
+	ld	b,#16
 
         ;; Optimise for the case when this side has 8 bits of data or
         ;; less.  This is often the case with support address calls.
-        or      a
-        jp      NZ,1$
-
+        jr      NZ,2$
         ld      b,#8
         ld      a,c
 1$:
         ;; Taken from z88dk, which originally borrowed from the
         ;; Spectrum rom.
         add     hl,hl
+2$:
         rl      c
         rla                     ;DLE 27/11/98
-        jr      NC,2$
+        jr      NC,3$
         add     hl,de
-2$:
+3$:
         djnz    1$
         ret
+