Author: Armin Rigo <ar...@tunes.org>
Branch:
Changeset: r63459:a1173abdf19e
Date: 2013-04-17 20:48 +0200
http://bitbucket.org/pypy/pypy/changeset/a1173abdf19e/
Log: Expand the comments. No actual change in the code.
diff --git a/rpython/jit/backend/x86/assembler.py
b/rpython/jit/backend/x86/assembler.py
--- a/rpython/jit/backend/x86/assembler.py
+++ b/rpython/jit/backend/x86/assembler.py
@@ -178,7 +178,8 @@
addr = self.cpu.gc_ll_descr.get_malloc_fn_addr('malloc_unicode')
else:
addr = self.cpu.gc_ll_descr.get_malloc_slowpath_array_addr()
- mc.SUB_ri(esp.value, 16 - WORD)
+ mc.SUB_ri(esp.value, 16 - WORD) # restore 16-byte alignment
+ # magically, the above is enough on X86_32 to reserve 3 stack places
if kind == 'fixed':
mc.SUB_rr(edi.value, eax.value) # compute the size we want
# the arg is already in edi
@@ -191,21 +192,23 @@
mc.MOV_rr(esi.value, ebp.value)
elif kind == 'str' or kind == 'unicode':
if IS_X86_32:
- # 1 for return value, 3 for alignment
- mc.MOV_rs(edi.value, WORD * (3 + 1 + 1))
+ # stack layout: [---][---][---][ret][gcmap][length]...
+ mc.MOV_rs(edi.value, WORD * 5) # pick 'length'
mc.MOV_sr(0, edi.value)
else:
+ # stack layout: [---][ret][gcmap][length]...
mc.MOV_rs(edi.value, WORD * 3)
else:
if IS_X86_32:
- mc.MOV_rs(edi.value, WORD * (3 + 1 + 1)) # itemsize
+ # stack layout: [--][--][--][ret][gcmap][itemsize][length][tid]
+ mc.MOV_rs(edi.value, WORD * 5) # pick 'itemsize'
mc.MOV_sr(0, edi.value)
- mc.MOV_rs(edi.value, WORD * (3 + 3 + 1))
- mc.MOV_sr(WORD, edi.value) # tid
- mc.MOV_rs(edi.value, WORD * (3 + 2 + 1))
- mc.MOV_sr(2 * WORD, edi.value) # length
+ mc.MOV_rs(edi.value, WORD * 7) # pick 'tid'
+ mc.MOV_sr(WORD, edi.value)
+ mc.MOV_rs(edi.value, WORD * 6) # pick 'length'
+ mc.MOV_sr(2 * WORD, edi.value)
else:
- # offset is 1 extra for call + 1 for SUB above
+ # stack layout: [---][ret][gcmap][itemsize][length][tid]...
mc.MOV_rs(edi.value, WORD * 3) # itemsize
mc.MOV_rs(esi.value, WORD * 5) # tid
mc.MOV_rs(edx.value, WORD * 4) # length
@@ -2425,7 +2428,7 @@
addr = self.malloc_slowpath_unicode
self.mc.MOV(RawEspLoc(WORD, INT), lengthloc)
# save the gcmap
- self.push_gcmap(self.mc, gcmap, mov=True)
+ self.push_gcmap(self.mc, gcmap, mov=True) # mov into RawEspLoc(0)
self.mc.CALL(imm(addr))
offset = self.mc.get_relative_pos() - jmp_adr1
assert 0 < offset <= 127
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