# SYS_clone = 120
# SYS_exit = 1
-# in order that the child can find the start func and its arg, we need to store it into
-# non-volative regs. to do so, we have to store those 2 regs into our stackframe, so
-# we can restore them later.
-subi 1, 1, 16
-stw 30, 12(1)
-stw 31, 8(1)
+# store non-volatile regs r30, r31 on stack in order to put our
+# start func and its arg there
+stwu 30, -16(1)
+stw 31, 4(1)
# save r3 (func) into r30, and r6(arg) into r31
mr 30, 3
sc
# check for syscall error
-#this code should be more efficient, but it borks
-#bns+ 1f # jump to label 1 if no summary overflow.
+bns+ 1f # jump to label 1 if no summary overflow.
#else
-#neg 3, 3 #negate the result (errno)
-#b 2f # jump to epilogue
-
-# this error check code at least does not spoil the clone call.
-#mfcr 0 # Check for an error
-#rlwinm 4, 0, 0, 3, 3 # by checking for bit 28.
-#cmplwi 0, 4, 0 # It is an error if non-zero.
-#beq 0, 1f # Jump if not an error.
-#neg 3, 3 # Negate the error number.
-#b 2f # jump to epilogue
+neg 3, 3 #negate the result (errno)
1:
# compare sc result with 0
cmpwi cr7, 3, 0
bne cr7, 2f
#else: we're the child
-#call funcptr
-# move arg (d) into r3
+#call funcptr: move arg (d) into r3
mr 3, 31
#move r30 (funcptr) into CTR reg
mtctr 30
2:
# restore stack
-lwz 30, 12(1)
-lwz 31, 8(1)
+lwz 30, 0(1)
+lwz 31, 4(1)
addi 1, 1, 16
blr
-
-
-