Propeller Manual
Table Of Contents
- Preface
- Chapter 1 : Introducing the Propeller Chip
- Concept
- Package Types
- Pin Descriptions
- Specifications
- Hardware Connections
- Boot Up Procedure
- Run-Time Procedure
- Shutdown Procedure
- Block Diagram
- Shared Resources
- System Clock
- Cogs (processors)
- Hub
- I/O Pins
- System Counter
- CLK Register
- Locks
- Main Memory
- Main RAM
- Main ROM
- Character Definitions
- Log and Anti-Log Tables
- Sine Table
- Boot Loader and Spin Interpreter
- Chapter 2 : Spin Language Reference
- Structure of Propeller Objects/Spin
- Categorical Listing of Propeller Spin Language
- Spin Language Elements
- ABORT
- BYTE
- BYTEFILL
- BYTEMOVE
- CASE
- CHIPVER
- CLKFREQ
- _CLKFREQ
- CLKMODE
- _CLKMODE
- CLKSET
- CNT
- COGID
- COGINIT
- COGNEW
- COGSTOP
- CON
- CONSTANT
- Constants (pre-defined)
- CTRA, CTRB
- DAT
- DIRA, DIRB
- FILE
- FLOAT
- _FREE
- FRQA, FRQB
- IF
- IFNOT
- INA, INB
- LOCKCLR
- LOCKNEW
- LOCKRET
- LOCKSET
- LONG
- LONGFILL
- LONGMOVE
- LOOKDOWN, LOOKDOWNZ
- LOOKUP, LOOKUPZ
- NEXT
- OBJ
- Operators
- Expression Workspace
- Operator Attributes
- Unary / Binary
- Normal / Assignment
- Constant and/or Variable Expression
- Level of Precedence
- Intermediate Assignments
- Constant Assignment ‘=’
- Variable Assignment ‘:=’
- Add ‘+’, ‘+=’
- Positive ‘+’ (unary form of Add)
- Subtract ‘-’, ‘-=’
- Negate ‘-’ (unary form of Subtract)
- Decrement, pre- or post- ‘- -’
- Increment, pre- or post- ‘+ +’
- Multiply, Return Low ‘*’, ‘*=’
- Multiply, Return High ‘**’, ‘**=’
- Divide ‘/’, ‘/=’
- Modulus ‘//’, ‘//=’
- Limit Minimum ‘#>’, ‘#>=’
- Limit Maximum ‘<#’, ‘<#=’
- Square Root ‘^^’
- Absolute Value ‘||’
- Sign-Extend 7 or Post-Clear ‘~’
- Sign-Extend 15 or Post-Set ‘~~’
- Shift Arithmetic Right ‘~>’, ‘~>=’
- Random ‘?’
- Bitwise Decode ‘|<’
- Bitwise Encode ‘>|’
- Bitwise Shift Left ‘<<’, ‘<<=’
- Bitwise Shift Right ‘>>’, ‘>>=’
- Bitwise Rotate Left ‘<-’, ‘<-=’
- Bitwise Rotate Right ‘->’, ‘->=’
- Bitwise Reverse ‘><’, ‘><=’
- Bitwise AND ‘&’, ‘&=’
- Bitwise OR ‘|’, ‘|=’
- Bitwise XOR ‘^’, ‘^=’
- Bitwise NOT ‘!’
- Boolean AND ‘AND’, ‘AND=’
- Boolean OR ‘OR’, ‘OR=’
- Boolean NOT ‘NOT’
- Boolean Is Equal ‘==’, ‘===’
- Boolean Is Not Equal ‘<>’, ‘<>=’
- Boolean Is Less Than ‘<’, ‘<=’
- Boolean Is Greater Than ‘>’, ‘>=’
- Boolean Is Equal or Less ‘=<’, ‘=<=’
- Boolean Is Equal or Greater ‘=>’, ‘=>=’
- Symbol Address ‘@’
- Object Address Plus Symbol ‘@@’
- OUTA, OUTB
- PAR
- PHSA, PHSB
- PRI
- PUB
- QUIT
- REBOOT
- REPEAT
- RESULT
- RETURN
- ROUND
- SPR
- _STACK
- STRCOMP
- STRING
- STRSIZE
- Symbols
- TRUNC
- VAR
- VCFG
- VSCL
- WAITCNT
- WAITPEQ
- WAITPNE
- WAITVID
- WORD
- WORDFILL
- WORDMOVE
- _XINFREQ
- Chapter 3 : Assembly Language Reference
- The Structure of Propeller Assembly
- Categorical Listing of Propeller Assembly Language
- Assembly Language Elements
- ABS
- ABSNEG
- ADD
- ADDABS
- ADDS
- ADDSX
- ADDX
- AND
- ANDN
- CALL
- CLKSET
- CMP
- CMPS
- CMPSUB
- CMPSX
- CMPX
- CNT
- COGID
- COGINIT
- COGSTOP
- Conditions ( IF_x )
- CTRA, CTRB
- DIRA, DIRB
- DJNZ
- Effects ( WC, WZ, WR, NR )
- FIT
- FRQA, FRQB
- HUBOP
- IF_x (Conditions)
- INA, INB
- JMP
- JMPRET
- LOCKCLR
- LOCKNEW
- LOCKRET
- LOCKSET
- MAX
- MAXS
- MIN
- MINS
- MOV
- MOVD
- MOVI
- MOVS
- MUXC
- MUXNC
- MUXNZ
- MUXZ
- NEG
- NEGC
- NEGNC
- NEGNZ
- NEGZ
- NOP
- NR
- Operators
- OR
- ORG
- OUTA, OUTB
- PAR
- PHSA, PHSB
- RCL
- RCR
- RDBYTE
- RDLONG
- RDWORD
- Registers
- RES
- RET
- REV
- ROL
- ROR
- SAR
- SHL
- SHR
- SUB
- SUBABS
- SUBS
- SUBSX
- SUBX
- SUMC
- SUMNC
- SUMZ
- Symbols
- TEST
- TESTN
- TJNZ
- TJZ
- VCFG
- VSCL
- WAITCNT
- WAITPEQ
- WAITPNE
- WAITVID
- WC
- WR
- WRBYTE
- WRLONG
- WRWORD
- WZ
- XOR
- Appendix A: Reserved Word List
- Appendix B: Math Samples and Function Tables
- Index
LOCKNEW – Spin Language Reference
Page 122 · Propeller Manual v1.1
LOCKNEW
Command: Check out a new lock and get its ID.
((PUB ┆ PRI))
LOCKNEW
Returns: ID (0-7) of the lock checked out, or -1 if none were available.
Explanation
LOCKNEW is one of four lock commands (LOCKNEW, LOCKRET, T LOCKSETT, and LOCKCLR) used to
manage resources that are user-defined and deemed mutually exclusive.
LOCKNEW checks out a
unique lock, from the Hub, and retrieves the ID of that lock. If no locks were available,
LOCKNEW returns -1.
About Locks
A lock is a semaphore mechanism that is used to communicate between two or more entities.
In the Propeller chip, a lock is simply one of eight global bits in a protected register within
the Hub. The Hub maintains an inventory of which locks are in use and their current states.
Cogs can check out, set, clear, and return locks as needed during run time to indicate whether
a custom shared item, such as a block of memory, is available or not. Since locks are
managed by the Hub only one cog can affect them at a time, making this an effective control
mechanism.
In applications where two or more cogs are sharing the same memory, a tool such as a lock
may be required to prevent catastrophic collisions from occurring. The Hub prevents such
collisions from occurring on elemental data (such a byte, word or long) at every moment in
time, but it cannot prevent “logical” collisions on blocks of multiple elements (such as a
block of bytes, words, longs or any combination of these). For example, if two or more cogs
are sharing a single byte of main memory, each one is guaranteed exclusive access to that
byte by nature of the Hub. But if those two cogs share multiple bytes of main memory, the
Hub can not prevent one cog from writing a few of those bytes while another cog is reading
all of them; all cogs’ interactions with those bytes may be interleaved in time. In this case,
the developer should design each process (in each cog that shares this memory) so that they
cooperatively share the memory block in a non-destructive way. Locks serve as flags that
notify each cog when a memory block is safe to manipulate or not.