h8300: library functions

[sfrench/cifs-2.6.git] / arch / h8300 / lib / udivsi3.S

diff --git a/arch/h8300/lib/udivsi3.S b/arch/h8300/lib/udivsi3.S
new file mode 100644 (file)
index 0000000..bbe6561
--- /dev/null
+++ b/arch/h8300/lib/udivsi3.S
@@ -0,0 +1,76 @@
+#include "libgcc.h"
+
+       ;; This function also computes the remainder and stores it in er3.
+       .global __udivsi3
+__udivsi3:
+       mov.w   A1E,A1E         ; denominator top word 0?
+       bne     DenHighNonZero
+
+       ; do it the easy way, see page 107 in manual
+       mov.w   A0E,A2
+       extu.l  A2P
+       divxu.w A1,A2P
+       mov.w   A2E,A0E
+       divxu.w A1,A0P
+       mov.w   A0E,A3
+       mov.w   A2,A0E
+       extu.l  A3P
+       rts
+
+       ; er0 = er0 / er1
+       ; er3 = er0 % er1
+       ; trashes er1 er2
+       ; expects er1 >= 2^16
+DenHighNonZero:
+       mov.l   er0,er3
+       mov.l   er1,er2
+#ifdef CONFIG_CPU_H8300H
+divmod_L21:
+       shlr.l  er0
+       shlr.l  er2             ; make divisor < 2^16
+       mov.w   e2,e2
+       bne     divmod_L21
+#else
+       shlr.l  #2,er2          ; make divisor < 2^16
+       mov.w   e2,e2
+       beq     divmod_L22A
+divmod_L21:
+       shlr.l  #2,er0
+divmod_L22:
+       shlr.l  #2,er2          ; make divisor < 2^16
+       mov.w   e2,e2
+       bne     divmod_L21
+divmod_L22A:
+       rotxl.w r2
+       bcs     divmod_L23
+       shlr.l  er0
+       bra     divmod_L24
+divmod_L23:
+       rotxr.w r2
+       shlr.l  #2,er0
+divmod_L24:
+#endif
+       ;; At this point,
+       ;;  er0 contains shifted dividend
+       ;;  er1 contains divisor
+       ;;  er2 contains shifted divisor
+       ;;  er3 contains dividend, later remainder
+       divxu.w r2,er0          ; r0 now contains the approximate quotient (AQ)
+       extu.l  er0
+       beq     divmod_L25
+       subs    #1,er0          ; er0 = AQ - 1
+       mov.w   e1,r2
+       mulxu.w r0,er2          ; er2 = upper (AQ - 1) * divisor
+       sub.w   r2,e3           ; dividend - 65536 * er2
+       mov.w   r1,r2
+       mulxu.w r0,er2          ; compute er3 = remainder (tentative)
+       sub.l   er2,er3         ; er3 = dividend - (AQ - 1) * divisor
+divmod_L25:
+       cmp.l   er1,er3         ; is divisor < remainder?
+       blo     divmod_L26
+       adds    #1,er0
+       sub.l   er1,er3         ; correct the remainder
+divmod_L26:
+       rts
+
+       .end