123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443 |
- @c Copyright (C) 2002-2022 Free Software Foundation, Inc.
- @c This is part of the GAS manual.
- @c For copying conditions, see the file as.texinfo.
- @ifset GENERIC
- @page
- @node MSP430-Dependent
- @chapter MSP 430 Dependent Features
- @end ifset
- @ifclear GENERIC
- @node Machine Dependencies
- @chapter MSP 430 Dependent Features
- @end ifclear
- @cindex MSP 430 support
- @cindex 430 support
- @menu
- * MSP430 Options:: Options
- * MSP430 Syntax:: Syntax
- * MSP430 Floating Point:: Floating Point
- * MSP430 Directives:: MSP 430 Machine Directives
- * MSP430 Opcodes:: Opcodes
- * MSP430 Profiling Capability:: Profiling Capability
- @end menu
- @node MSP430 Options
- @section Options
- @cindex MSP 430 options (none)
- @cindex options for MSP430 (none)
- @table @code
- @item -mmcu
- selects the mcu architecture. If the architecture is 430Xv2 then this
- also enables NOP generation unless the @option{-mN} is also specified.
- @item -mcpu
- selects the cpu architecture. If the architecture is 430Xv2 then this
- also enables NOP generation unless the @option{-mN} is also specified.
- @item -msilicon-errata=@var{name}[,@var{name}@dots{}]
- Implements a fixup for named silicon errata. Multiple silicon errata
- can be specified by multiple uses of the @option{-msilicon-errata}
- option and/or by including the errata names, separated by commas, on
- an individual @option{-msilicon-errata} option. Errata names
- currently recognised by the assembler are:
- @table @code
- @item cpu4
- @code{PUSH #4} and @option{PUSH #8} need longer encodings on the
- MSP430. This option is enabled by default, and cannot be disabled.
- @item cpu8
- Do not set the @code{SP} to an odd value.
- @item cpu11
- Do not update the @code{SR} and the @code{PC} in the same instruction.
- @item cpu12
- Do not use the @code{PC} in a @code{CMP} or @code{BIT} instruction.
- @item cpu13
- Do not use an arithmetic instruction to modify the @code{SR}.
- @item cpu19
- Insert @code{NOP} after @code{CPUOFF}.
- @end table
- @item -msilicon-errata-warn=@var{name}[,@var{name}@dots{}]
- Like the @option{-msilicon-errata} option except that instead of
- fixing the specified errata, a warning message is issued instead.
- This option can be used alongside @option{-msilicon-errata} to
- generate messages whenever a problem is fixed, or on its own in order
- to inspect code for potential problems.
- @item -mP
- enables polymorph instructions handler.
- @item -mQ
- enables relaxation at assembly time. DANGEROUS!
- @item -ml
- indicates that the input uses the large code model.
- @item -mn
- enables the generation of a NOP instruction following any instruction
- that might change the interrupts enabled/disabled state. The
- pipelined nature of the MSP430 core means that any instruction that
- changes the interrupt state (@code{EINT}, @code{DINT}, @code{BIC #8,
- SR}, @code{BIS #8, SR} or @code{MOV.W <>, SR}) must be
- followed by a NOP instruction in order to ensure the correct
- processing of interrupts. By default it is up to the programmer to
- supply these NOP instructions, but this command-line option enables
- the automatic insertion by the assembler, if they are missing.
- @item -mN
- disables the generation of a NOP instruction following any instruction
- that might change the interrupts enabled/disabled state. This is the
- default behaviour.
- @item -my
- tells the assembler to generate a warning message if a NOP does not
- immediately follow an instruction that enables or disables
- interrupts. This is the default.
- Note that this option can be stacked with the @option{-mn} option so
- that the assembler will both warn about missing NOP instructions and
- then insert them automatically.
- @item -mY
- disables warnings about missing NOP instructions.
- @item -md
- mark the object file as one that requires data to copied from ROM to
- RAM at execution startup. Disabled by default.
- @item -mdata-region=@var{region}
- Select the region data will be placed in.
- Region placement is performed by the compiler and linker. The only effect this
- option will have on the assembler is that if @var{upper} or @var{either} is
- selected, then the symbols to initialise high data and bss will be defined.
- Valid @var{region} values are:
- @table @code
- @item none
- @item lower
- @item upper
- @item either
- @end table
- @end table
- @node MSP430 Syntax
- @section Syntax
- @menu
- * MSP430-Macros:: Macros
- * MSP430-Chars:: Special Characters
- * MSP430-Regs:: Register Names
- * MSP430-Ext:: Assembler Extensions
- @end menu
- @node MSP430-Macros
- @subsection Macros
- @cindex Macros, MSP 430
- @cindex MSP 430 macros
- The macro syntax used on the MSP 430 is like that described in the MSP
- 430 Family Assembler Specification. Normal @code{@value{AS}}
- macros should still work.
- Additional built-in macros are:
- @table @code
- @item llo(exp)
- Extracts least significant word from 32-bit expression 'exp'.
- @item lhi(exp)
- Extracts most significant word from 32-bit expression 'exp'.
- @item hlo(exp)
- Extracts 3rd word from 64-bit expression 'exp'.
- @item hhi(exp)
- Extracts 4rd word from 64-bit expression 'exp'.
- @end table
- They normally being used as an immediate source operand.
- @smallexample
- mov #llo(1), r10 ; == mov #1, r10
- mov #lhi(1), r10 ; == mov #0, r10
- @end smallexample
- @node MSP430-Chars
- @subsection Special Characters
- @cindex line comment character, MSP 430
- @cindex MSP 430 line comment character
- A semicolon (@samp{;}) appearing anywhere on a line starts a comment
- that extends to the end of that line.
- If a @samp{#} appears as the first character of a line then the whole
- line is treated as a comment, but it can also be a logical line number
- directive (@pxref{Comments}) or a preprocessor control command
- (@pxref{Preprocessing}).
- @cindex line separator, MSP 430
- @cindex statement separator, MSP 430
- @cindex MSP 430 line separator
- Multiple statements can appear on the same line provided that they are
- separated by the @samp{@{} character.
- @cindex identifiers, MSP 430
- @cindex MSP 430 identifiers
- The character @samp{$} in jump instructions indicates current location and
- implemented only for TI syntax compatibility.
- @node MSP430-Regs
- @subsection Register Names
- @cindex MSP 430 register names
- @cindex register names, MSP 430
- General-purpose registers are represented by predefined symbols of the
- form @samp{r@var{N}} (for global registers), where @var{N} represents
- a number between @code{0} and @code{15}. The leading
- letters may be in either upper or lower case; for example, @samp{r13}
- and @samp{R7} are both valid register names.
- @cindex special purpose registers, MSP 430
- Register names @samp{PC}, @samp{SP} and @samp{SR} cannot be used as register names
- and will be treated as variables. Use @samp{r0}, @samp{r1}, and @samp{r2} instead.
- @node MSP430-Ext
- @subsection Assembler Extensions
- @cindex MSP430 Assembler Extensions
- @table @code
- @item @@rN
- As destination operand being treated as @samp{0(rn)}
- @item 0(rN)
- As source operand being treated as @samp{@@rn}
- @item jCOND +N
- Skips next N bytes followed by jump instruction and equivalent to
- @samp{jCOND $+N+2}
- @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
- @cindex floating point, MSP 430 (@sc{ieee})
- @cindex MSP 430 floating point (@sc{ieee})
- The MSP 430 family uses @sc{ieee} 32-bit floating-point numbers.
- @node MSP430 Directives
- @section MSP 430 Machine Directives
- @cindex machine directives, MSP 430
- @cindex MSP 430 machine directives
- @table @code
- @cindex @code{file} directive, MSP 430
- @item .file
- This directive is ignored; it is accepted for compatibility with other
- MSP 430 assemblers.
- @quotation
- @emph{Warning:} in other versions of the @sc{gnu} assembler, @code{.file} is
- used for the directive called @code{.app-file} in the MSP 430 support.
- @end quotation
- @cindex @code{line} directive, MSP 430
- @item .line
- This directive is ignored; it is accepted for compatibility with other
- MSP 430 assemblers.
- @cindex @code{arch} directive, MSP 430
- @item .arch
- Sets the target microcontroller in the same way as the @option{-mmcu}
- command-line option.
- @cindex @code{cpu} directive, MSP 430
- @item .cpu
- Sets the target architecture in the same way as the @option{-mcpu}
- command-line option.
- @cindex @code{profiler} directive, MSP 430
- @item .profiler
- This directive instructs assembler to add new profile entry to the object file.
- @cindex @code{refsym} directive, MSP 430
- @item .refsym
- This directive instructs assembler to add an undefined reference to
- the symbol following the directive. The maximum symbol name length is
- 1023 characters. No relocation is created for this symbol; it will
- exist purely for pulling in object files from archives. Note that
- this reloc is not sufficient to prevent garbage collection; use a
- KEEP() directive in the linker file to preserve such objects.
- @cindex @code{mspabi_attribute} directive, MSP430
- @item .mspabi_attribute
- This directive tells the assembler what the MSPABI build attributes for this
- file are. This is used for validating the command line options passed to
- the assembler against the options the original source file was compiled with.
- The expected format is:
- @samp{.mspabi_attribute tag_name, tag_value}
- For example, to set the tag @code{OFBA_MSPABI_Tag_ISA} to @code{MSP430X}:
- @samp{.mspabi_attribute 4, 2}
- See the @cite{MSP430 EABI, document slaa534} for the details on tag names and
- values.
- @end table
- @node MSP430 Opcodes
- @section Opcodes
- @cindex MSP 430 opcodes
- @cindex opcodes for MSP 430
- @code{@value{AS}} implements all the standard MSP 430 opcodes. No
- additional pseudo-instructions are needed on this family.
- For information on the 430 machine instruction set, see @cite{MSP430
- User's Manual, document slau049d}, 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
|