| @c Copyright 2002, 2004, 2005, 2011 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 -m |
| select the mpu arch. Currently has no effect. |
| @item -mP |
| enables polymorph instructions handler. |
| |
| @item -mQ |
| enables relaxation at assembly time. DANGEROUS! |
| |
| @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{sect} directive, MSP 430 |
| @item .arch |
| 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 |
| @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 |
