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Diffstat (limited to 'gas/doc/c-msp430.texi')
| -rw-r--r-- | gas/doc/c-msp430.texi | 150 |
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 |