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authorNick Clifton <nickc@redhat.com>2004-08-25 12:54:15 +0000
committerNick Clifton <nickc@redhat.com>2004-08-25 12:54:15 +0000
commitb18c562e39c5c3ee63032a9a0aa9b7571343fd58 (patch)
tree0a1ab4cf2ca014da6f955028f9410e6b59ce57e8 /gas/doc
parent61f5d0545d98ab8252082db2bf10cdd40af51cee (diff)
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Apply Dmitry Diky's patches to add relaxation to msp430.
Diffstat (limited to 'gas/doc')
-rw-r--r--gas/doc/c-msp430.texi150
1 files changed, 149 insertions, 1 deletions
diff --git a/gas/doc/c-msp430.texi b/gas/doc/c-msp430.texi
index 0050359..b398952 100644
--- a/gas/doc/c-msp430.texi
+++ b/gas/doc/c-msp430.texi
@@ -1,4 +1,4 @@
-@c Copyright 2002 Free Software Foundation, Inc.
+@c Copyright 2002, 2004 Free Software Foundation, Inc.
@c This is part of the GAS manual.
@c For copying conditions, see the file as.texinfo.
@ifset GENERIC
@@ -19,6 +19,7 @@
* MSP430 Floating Point:: Floating Point
* MSP430 Directives:: MSP 430 Machine Directives
* MSP430 Opcodes:: Opcodes
+* MSP430 Profiling Capability:: Profiling Capability
@end menu
@node MSP430 Options
@@ -116,6 +117,54 @@ Skips next N bytes followed by jump instruction and equivalent to
@end table
+Also, there are some instructions, which cannot be found in other assemblers.
+These are branch instructions, which has different opcodes upon jump distance.
+They all got PC relative addressing mode.
+
+@table @code
+@item beq label
+A polymorph instruction which is @samp{jeq label} in case if jump distance
+within allowed range for cpu's jump instruction. If not, this unrolls into
+a sequence of
+@smallexample
+ jne $+6
+ br label
+@end smallexample
+
+@item bne label
+A polymorph instruction which is @samp{jne label} or @samp{jeq +4; br label}
+
+@item blt label
+A polymorph instruction which is @samp{jl label} or @samp{jge +4; br label}
+
+@item bltn label
+A polymorph instruction which is @samp{jn label} or @samp{jn +2; jmp +4; br label}
+
+@item bltu label
+A polymorph instruction which is @samp{jlo label} or @samp{jhs +2; br label}
+
+@item bge label
+A polymorph instruction which is @samp{jge label} or @samp{jl +4; br label}
+
+@item bgeu label
+A polymorph instruction which is @samp{jhs label} or @samp{jlo +4; br label}
+
+@item bgt label
+A polymorph instruction which is @samp{jeq +2; jge label} or @samp{jeq +6; jl +4; br label}
+
+@item bgtu label
+A polymorph instruction which is @samp{jeq +2; jhs label} or @samp{jeq +6; jlo +4; br label}
+
+@item bleu label
+A polymorph instruction which is @samp{jeq label; jlo label} or @samp{jeq +2; jhs +4; br label}
+
+@item ble label
+A polymorph instruction which is @samp{jeq label; jl label} or @samp{jeq +2; jge +4; br label}
+
+@item jump label
+A polymorph instruction which is @samp{jmp label} or @samp{br label}
+@end table
+
@node MSP430 Floating Point
@section Floating Point
@@ -150,6 +199,10 @@ MSP 430 assemblers.
Currently this directive is ignored; it is accepted for compatibility with other
MSP 430 assemblers.
+@cindex @code{profiler} directive, MSP 430
+@item .profiler
+This directive instructs assembler to add new profile entry to the object file.
+
@end table
@node MSP430 Opcodes
@@ -162,3 +215,98 @@ additional pseudo-instructions are needed on this family.
For information on the 430 machine instruction set, see @cite{MSP430
User's Manual, document slau049b}, Texas Instrument, Inc.
+
+@node MSP430 Profiling Capability
+@section Profiling Capability
+
+@cindex MSP 430 profiling capability
+@cindex profiling capability for MSP 430
+It is a performance hit to use gcc's profiling approach for this tiny target.
+Even more -- jtag hardware facility does not perform any profiling functions.
+However we've got gdb's built-in simulator where we can do anything.
+
+We define new section @samp{.profiler} which holds all profiling information.
+We define new pseudo operation @samp{.profiler} which will instruct assembler to
+add new profile entry to the object file. Profile should take place at the
+present address.
+
+Pseudo operation format:
+
+@samp{.profiler flags,function_to_profile [, cycle_corrector, extra]}
+
+
+where:
+
+@table @code
+
+@table @code
+
+@samp{flags} is a combination of the following characters:
+
+@item s
+function entry
+@item x
+function exit
+@item i
+function is in init section
+@item f
+function is in fini section
+@item l
+library call
+@item c
+libc standard call
+@item d
+stack value demand
+@item I
+interrupt service routine
+@item P
+prologue start
+@item p
+prologue end
+@item E
+epilogue start
+@item e
+epilogue end
+@item j
+long jump / sjlj unwind
+@item a
+an arbitrary code fragment
+@item t
+extra parameter saved (a constant value like frame size)
+@end table
+
+@item function_to_profile
+a function address
+@item cycle_corrector
+a value which should be added to the cycle counter, zero if omitted.
+@item extra
+any extra parameter, zero if omitted.
+
+@end table
+
+For example:
+@smallexample
+.global fxx
+.type fxx,@@function
+fxx:
+.LFrameOffset_fxx=0x08
+.profiler "scdP", fxx ; function entry.
+ ; we also demand stack value to be saved
+ push r11
+ push r10
+ push r9
+ push r8
+.profiler "cdpt",fxx,0, .LFrameOffset_fxx ; check stack value at this point
+ ; (this is a prologue end)
+ ; note, that spare var filled with
+ ; the farme size
+ mov r15,r8
+...
+.profiler cdE,fxx ; check stack
+ pop r8
+ pop r9
+ pop r10
+ pop r11
+.profiler xcde,fxx,3 ; exit adds 3 to the cycle counter
+ ret ; cause 'ret' insn takes 3 cycles
+@end smallexample