summaryrefslogtreecommitdiffstats
path: root/arch/h8300/lib/udivsi3.S
diff options
context:
space:
mode:
Diffstat (limited to 'arch/h8300/lib/udivsi3.S')
-rw-r--r--arch/h8300/lib/udivsi3.S76
1 files changed, 76 insertions, 0 deletions
diff --git a/arch/h8300/lib/udivsi3.S b/arch/h8300/lib/udivsi3.S
new file mode 100644
index 000000000000..bbe65610f316
--- /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