Editors note:
This page was assembled from bits of the http://www.bitscope.com site for the purposes of highlighting the brilliance of the design. Another (less brilliant) language that uses this sort of syntax called meta-l is being developed.
The command set for the BitScope Virtual machine is a subset of the bytes values between 0 and 255. Initially, active commands are confined to the ASCII range from 0 to 128. Where ever possible, command values correspond to a character with a meaning related to the command function. This makes the byte-codes human readable - with some practice.
The general scheme for allocating byte-code values and their ASCII symbol is as follows:
| numerals | used for entering data | |
| operators | manipulation of register values | |
| lower case | general machine operation | |
| upper case | major machine functions | |
| non-printables | reserved for future commands |
Unused bytecodes will be echoed if printable, else ignored.
| Hex | ASCII | Name | Description |
|---|---|---|---|
| 00 | (null) | Reset | Reset the machine. Print the machine ID string |
| 23 | # | Load Source Register | Store R0 into R2. Set up R2 which is a source Register. A Register to Register move may be done by pointing to a source (R2) and destination (R1). |
| 2b | + | Inc REG | Increment the register pointed to by R1 |
| 2d | - | Dec REG | Decrement the register pointed to by R1 |
| 30 | 0 | Enter nibble 0 | Increment R0 by 0 and nibble swap R0 |
| 31 | 1 | Enter nibble 1 | Increment R0 by 1 and nibble swap R0 |
| 32 | 2 | Enter nibble 2 | Increment R0 by 2 and nibble swap R0 |
| 33 | 3 | Enter nibble 3 | Increment R0 by 3 and nibble swap R0 |
| 34 | 4 | Enter nibble 4 | Increment R0 by 4 and nibble swap R0 |
| 35 | 5 | Enter nibble 5 | Increment R0 by 5 and nibble swap R0 |
| 36 | 6 | Enter nibble 6 | Increment R0 by 6 and nibble swap R0 |
| 37 | 7 | Enter nibble 7 | Increment R0 by 7 and nibble swap R0 |
| 38 | 8 | Enter nibble 8 | Increment R0 by 8 and nibble swap R0 |
| 39 | 9 | Enter nibble 9 | Increment R0 by 9 and nibble swap R0 |
| 3c | < | Get counter value from Spock | Shift the current 16 bit counter value from Spock into R9, R10 |
| 3e | > | Program Spock from Registers | Load 5 bytes of data from R3..R7 into Spock. Previous contents of counter are destroyed |
| 3f | ? | Print Machine ID | Print <CR>Char8..CHAR1<CR> where CHARn is part of a string which identifies the type and revision of this device. |
| 40 | @ | Load Address Register | Store R0 into R1. Use to set up register pointer |
| 53 | S | Dump Sample RAM (CSV) | Dump lines of 16 Sample Ram values - digital and analog.
<CR> ddaa,ddaa,ddaa,.....................ddaa,ddaa<CR> ddaa,ddaa,ddaa,.....................ddaa,ddaa<CR> |
| 54 | T | Trace with TRIG stop | Begin Sample with OPTION mode, until TRIG then DELAY, Halt Sample Clk, and print Sample Address. |
| 5b | [ | Clear R0 | Register R0 is cleared. This usually precedes a nibble load |
| 5d | ] | Nibble swap R0 | R0:(0..3) is swapped with R0:(4..7). This operation follows a nibble entry and puts the entered nibbles in the correct order. |
| 61 | a | Enter nibble ‘a’ hex | Increment R0 by 10 and nibble swap R0 |
| 62 | b | Enter nibble ‘b’ hex | Increment R0 by 11 and nibble swap R0 |
| 63 | c | Enter nibble ‘c’ hex | Increment R0 by 12 and nibble swap R0 |
| 64 | d | Enter nibble ‘d’ hex | Increment R0 by 13 and nibble swap R0 |
| 65 | e | Enter nibble ‘e’ hex | Increment R0 by 14 and nibble swap R0 |
| 66 | f | Enter nibble ‘f’ hex | Increment R0 by 15 and nibble swap R0 |
| 6c | l | Load R0 from @R2 | Copy contents of register pointed to by R2 to R0 |
| 6e | n | Next Address | Increment address register R1 |
| 70 | p | Print REG value @R1 | Print <CR>ASCII,ASCII<CR> |
| 73 | s | Store R0 to @R1 | Copy contents of R0 to register pointed to by R1 |
| 75 | u | Update RAM pointers | Copy contents of R3,4 to R9,10. Updates Sample Address value from Sample Preload registers. |
| 78 | x | Exchange byte with POD | Transmit byte in POD_TX to POD IO-0. Wait for reply byte on IO-1 and put it in POD_RX then return it to Host |
| 7c | | | Pass Through byte to POD | Transmit byte in POD_TX to POD IO-0. Connect IO-1 to Serial Out for Host. |
Examples:
| [6]@[5a]s | loading R6 with 0x5a is: |
| [3]@ | enter 3 into R0, then copy it to R1 |
| []s | enter 0 into R0, then store it at (R1) |
| ns | increment R1 to 4, then store R0 at (R1) |
| [aa]ns | enter aa in R0, inc R1, then store R0 at (R1) |
| [f]ns | enter f in R0, inc R1, then store R0 at (R1) |
| []ns | enter 0 in Ro, inc R1, then store R0 at (R1) |
| [12]@[70]s| | set up R1, then ‘p’ |
| 4d | the response will be piped through |
| [54]s| | send the POD a ‘T’ |
| 506f | the response will be piped through |
| > | we are back talking to BitScope |
The BitScope virtual machine has a set of 20 Registers R0..R19. The operation
of the machine and all its instructions refer to these registers. All other
resources in the PIC are outside the scope of the virtual machine. The function
of all registers are detailed below. In some cases related commands are shown
as examples of how these registers are used.
| Rn | Register Description | Example of Register Use |
| R0 | Byte Input Register assemble input data here | [ clear R0 0..f inc R0 by 0..f , nibble swap ] nibble swap R0 |
| R1 | Register Pointer - pointer to R(0..ff) | @ copy R0 to R1 s move contents of R0 to R(R1) - s(tore) |
| R2 | Register Source - pointer to R(0..ff) | # copy R0 to R2 l move contents of R(R2) to R0 - l(oad) |
| R3 | Sample Preload L low byte of RAM addr to load to Spock | |
| R4 | Sample Preload H high byte of RAM addr to load to Spock | |
| R5 | TRIG Logic Byte - Logic levels for Spock to match | - loaded during Spock Init |
| R6 | TRIG Mask Byte - Don?t Care bits in trigger match | - loaded during Spock Init |
| R7 | Spock OPTION byte TRIG and PG1 | - setup in Spock |
| R8 | Trace Register Trace Option controls Sample operation of BitScope Machine | R8(0..3) - 4 bit vector to different Trigger and Chop modes. R8(4..7) - 4 bit pointer to select one of the Data bus MUX device channels |
| R9 | Counter capture Lo Counter low byte shifted out of Spock | |
| R10 | Counter capture Hi Counter high byte shifted out of Spock | |
| R11 | DELAY-L Post TRIG delay before halting | |
| R12 | DELAY-H Post TRIG delay before halting | |
| R13 | TimeBase TimeBase expander count | |
| R14 | Channel-A/B Channel Range settings for Chop | - H/L nibbles contain alternate values for RA(0..3) |
| R15 | Dump Length - Counter for number of Samples transmitted per request | |
| R16 | EEPROM Data data register for EEPROM | |
| R17 | EEPROM Address address register for EEPROM | |
| R18 | POD Transmit Register holds byte for POD | |
| R19 | POD Receive Register gets byte from POD |