powerpc/boot: Add extended precision shifts to the boot wrapper.

The upcomming currituck patches will need to do 64-bit shifts which will
fail with undefined symbol without this patch.

I looked at linking against libgcc but we can't guarantee that libgcc
was compiled with soft-float.  Also Using ../lib/div64.S or
../kernel/misc_32.S, this will break the build as the .o's need to be
built with different flags for the bootwrapper vs the kernel.  So for
now the easyest option is to just copy code from
arch/powerpc/kernel/misc_32.S  I don't think this code changes too often ;P

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Josh Boyer <jwboyer@gmail.com>

1 files changed, 52 insertions, 0 deletions

diff --git a/arch/powerpc/boot/div64.S b/arch/powerpc/boot/div64.S
index d271ab542673..bbcb8a4cc121 100644
--- a/arch/powerpc/boot/div64.S
+++ b/arch/powerpc/boot/div64.S
@@ -57,3 +57,55 @@ __div64_32:
         stw     r8,4(r3)
         mr      r3,r6           # return the remainder in r3
         blr
+
+/*
+ * Extended precision shifts.
+ *
+ * Updated to be valid for shift counts from 0 to 63 inclusive.
+ * -- Gabriel
+ *
+ * R3/R4 has 64 bit value
+ * R5    has shift count
+ * result in R3/R4
+ *
+ *  ashrdi3: arithmetic right shift (sign propagation)  
+ *  lshrdi3: logical right shift
+ *  ashldi3: left shift
+ */
+        .globl __ashrdi3
+__ashrdi3:
+        subfic  r6,r5,32
+        srw     r4,r4,r5        # LSW = count > 31 ? 0 : LSW >> count
+        addi    r7,r5,32        # could be xori, or addi with -32
+        slw     r6,r3,r6        # t1 = count > 31 ? 0 : MSW << (32-count)
+        rlwinm  r8,r7,0,32      # t3 = (count < 32) ? 32 : 0
+        sraw    r7,r3,r7        # t2 = MSW >> (count-32)
+        or      r4,r4,r6        # LSW |= t1
+        slw     r7,r7,r8        # t2 = (count < 32) ? 0 : t2
+        sraw    r3,r3,r5        # MSW = MSW >> count
+        or      r4,r4,r7        # LSW |= t2
+        blr
+
+        .globl __ashldi3
+__ashldi3:
+        subfic  r6,r5,32
+        slw     r3,r3,r5        # MSW = count > 31 ? 0 : MSW << count
+        addi    r7,r5,32        # could be xori, or addi with -32
+        srw     r6,r4,r6        # t1 = count > 31 ? 0 : LSW >> (32-count)
+        slw     r7,r4,r7        # t2 = count < 32 ? 0 : LSW << (count-32)
+        or      r3,r3,r6        # MSW |= t1
+        slw     r4,r4,r5        # LSW = LSW << count
+        or      r3,r3,r7        # MSW |= t2
+        blr
+
+        .globl __lshrdi3
+__lshrdi3:
+        subfic  r6,r5,32
+        srw     r4,r4,r5        # LSW = count > 31 ? 0 : LSW >> count
+        addi    r7,r5,32        # could be xori, or addi with -32
+        slw     r6,r3,r6        # t1 = count > 31 ? 0 : MSW << (32-count)
+        srw     r7,r3,r7        # t2 = count < 32 ? 0 : MSW >> (count-32)
+        or      r4,r4,r6        # LSW |= t1
+        srw     r3,r3,r5        # MSW = MSW >> count
+        or      r4,r4,r7        # LSW |= t2
+        blr