SVM is a simple process virtual machine that allows you to run a program written in Sister Assembly Language (SASM) or run a KEI file (compiled SASM file)
- SVM has 16 registers (0 to 15) of 2 bytes each
- SVM has memory of 65536 bytes (0 to 65535)
- SVM only handles signed integer of 8-bit and 16-bit, but for memory address it uses unsigned integer of 16-bit
- SVM also has a program counter (PC) which always points to the next instruction
To build both interpreter and compiler, execute:
$ make
To build interpreter only, execute:
$ make svm
To build compiler only, execute:
$ make svmc
$ svm <sasm file>
$ svm -kei <kei file>
$ svmc <sasm file 1> <sasm file 2> <sasm file...>
| Symbol | Description |
|---|---|
$x |
x-th register, i.e. $0 is 0-th register |
M[x] |
Memory at address x, i.e. M[65535] is memory at 65535 |
.xyz |
Label to mark the next instruction. Label starts with "." character |
@func |
Library call name |
| Command Name | Syntax | Description |
|---|---|---|
| No Operation | nop |
Self-explanatory. |
| Start | start |
Start of the program to run. A program must has exactly 1 start command. |
| Add | add $t $r $s |
$t = $r + $s |
| Add Immediate | addi $t $r C |
$t = $r + C. C is 16-bit integer. |
| Substract | sub $t $r $s |
$t = $r - $s |
| Multiply | mul $t $r $s |
$t = $r * $s |
| And | and $t $r $s |
$t = $r && $s |
| Or | or $t $r $s |
`$t = $r |
| Not | not $t $r |
$t = !$r |
| Equal | eq $t $r $s |
$t = $r == $s |
| Less Than | lt $t $r $s |
$t = $r < $s |
| Greater Than | gt $t $r $s |
$t = $r > $s |
| Load | ld $t $r C |
$t = M[$r+C:$r+C+1]. C is integer of 16-bit. Takes 16-bit from M[$r+C] and M[$r+C+1] with little indian format. |
| Load Byte | lb $t $r C |
$t = M[$r+C]. C is integer of 16-bit. Takes 8-bit from M[$r+C]. |
| Load Immediate | ldi $t C |
$t = C. C is integer of 16-bit. |
| Store | str $t $r C |
M[$r+C:$r+C+1] = $t. C is integer of 16-bit. Stored in little endian format. |
| Store Byte | stb $t $r C |
M[$r+C] = $t. C is integer of 16-bit. |
| Jump If Zero | jz $t .label |
if ($t == 0) PC = .label |
| Jump If Not Zero | jnz $t .label |
if ($t != 0) PC = .label |
| Jump | jmp .label |
PC = .label |
| Jump Register | jr $t |
PC = $t |
| Jump And Link | jal $t .label |
$t = next(PC); PC = .label |
| Library Call | libc $t $r @func |
func(out $t, $r) |
| Halt | halt |
Stops execution. A program must has at least 1 halt command. |
| Comment | # comment |
Comment in source code, not executed. |
| Open Library | lopen fname |
Open library named "fname". |
| Link | link @func |
Link a function named "func" to library call. "func" is taken from the last opened library. |
# simple test program
# read integer a & b, returns a + b
start
libc $0 $0 @input
libc $1 $1 @input
add $2 $0 $1
libc $2 $2 @output
halt