[pypy-commit] pypy s390x-backend: correct positioning of the ptr to write

[plan_rich]

Author: Richard Plangger <planrichi at gmail.com>
Branch: s390x-backend
Changeset: r82871:89a10fc86c4b
Date: 2016-03-07 20:47 +0100
http://bitbucket.org/pypy/pypy/changeset/89a10fc86c4b/

Log:	correct positioning of the ptr to write

diff --git a/rpython/jit/backend/ppc/opassembler.py b/rpython/jit/backend/ppc/opassembler.py
--- a/rpython/jit/backend/ppc/opassembler.py
+++ b/rpython/jit/backend/ppc/opassembler.py
@@ -884,9 +884,8 @@
                 return     # nothing to do
 
         if startindex_loc.is_imm():
-            self.mc.load_imm(r.SCRATCH, startindex_loc.value)
-            startindex_loc = r.SCRATCH
-
+            self.mc.load_imm(r.SCRATCH2, startindex_loc.value)
+            startindex_loc = r.SCRATCH2
         if ofs_loc.is_imm():
             self.mc.addi(r.SCRATCH2.value, startindex_loc.value, ofs_loc.value)
         else:
@@ -897,6 +896,7 @@
         # ofs_loc is now the real address pointing to the first
         # byte to be zeroed
 
+        prev_length_loc = length_loc
         if length_loc.is_imm():
             self.mc.load_imm(r.SCRATCH, length_loc.value)
             length_loc = r.SCRATCH
@@ -905,7 +905,7 @@
         jlt_location = self.mc.currpos()
         self.mc.trap()
 
-        self.mc.sradi(r.SCRATCH.value, length_loc.value, shift_by, 0)
+        self.mc.sradi(r.SCRATCH.value, length_loc.value, shift_by, 31)
         self.mc.mtctr(r.SCRATCH.value) # store the length in count register
 
         self.mc.li(r.SCRATCH.value, 0)
@@ -914,6 +914,8 @@
         # and length. Thus we zero 4/8 bytes in a loop in 1) and every remaining
         # byte is zeroed in another loop in 2)
 
+        self.mc.subi(ofs_loc.value, ofs_loc.value, stepsize)
+
         # first store of case 1)
         # 1) The next loop copies WORDS into the memory chunk starting at startindex
         # ending at startindex + length. These are bytes
@@ -921,6 +923,8 @@
         self.eza_stXu(r.SCRATCH.value, ofs_loc.value, stepsize, stepsize)
         self.mc.bdnz(loop_location - self.mc.currpos())
 
+        self.mc.addi(ofs_loc.value, ofs_loc.value, stepsize)
+
         pmc = OverwritingBuilder(self.mc, jlt_location, 1)
         pmc.blt(self.mc.currpos() - jlt_location)    # jump if length < WORD
         pmc.overwrite()
@@ -930,6 +934,7 @@
         # need to write the last bytes.
 
         # move the last bytes to the count register
+        length_loc = prev_length_loc
         if length_loc.is_imm():
             self.mc.load_imm(r.SCRATCH, length_loc.value & (stepsize-1))
         else:
@@ -942,6 +947,8 @@
         self.mc.mtctr(r.SCRATCH.value)
         self.mc.li(r.SCRATCH.value, 0)
 
+        self.mc.subi(ofs_loc.value, ofs_loc.value, 1)
+
         loop_position = self.mc.currpos()
         self.eza_stXu(r.SCRATCH.value, ofs_loc.value, 1, 1)
         self.mc.bdnz(self.mc.currpos() - loop_location)