Add string input interrupt from STDIN

README.md

@@ -89,22 +89,22 @@ There is currently no strict checking, so be careful.
 ## Directives
 
 - `DECLARE` declares the first label argument to equal the second, immediate
-value, argument and is used to declare a constant for the virtual machine.
+	value, argument and is used to declare a constant for the virtual machine.
 
 ### Operands
 
 - `addi` add the first to the second argument and store the result in the third
-argument
+	argument
 - `subi` subtract the first from the second argument and store the result in
-the third argument
+	the third argument
 - `divi` divide the first by the second argument and store the result in the
-third argument
+	third argument
 - `muli` multiply the first by the second argument and store the result in the
-third argument
+	third argument
 - `shli` shift left the first argument by the number of positions given by the
-second argument and store the result in the third argument
+	second argument and store the result in the third argument
 - `shri` shift right the first argument by the number of positions given by the
-second argument and store the result in the third argument
+	second argument and store the result in the third argument
 - `seti` set the first register argument to the second argument
 - `int` calls the interrupt specified by the first (integer) argument
 
@@ -112,15 +112,15 @@ second argument and store the result in the third argument
 
 - `jmp` jump to the label given by the first argument
 - `call` put the next statement to execute on the stack and jump to the label
-given by the first argument
+	given by the first argument
 - `ret` pop the the next statement to execute off the stack, e.g. returning to
-the next execution statement before calling `call`
+	the next execution statement before calling `call`
 - `lti` execute next statement if argument 1 is less than argument 2 else skip
-the next statement
+	the next statement
 - `gti` execute next statement if argument 1 is greater than argument 2 else
-skip the next statement
+	skip the next statement
 - `eqi` execute the next statement if argument 1 is equal to argument 2 else
-skip the next statement
+	skip the next statement
 
 ## Memory
 
@@ -137,5 +137,8 @@ the first argument
 	- `2` put value of register A as hexadecimal integer on stdout
 	- `3` put the string pointed at by register A for the amount of characters
 	defined by register B on stdout
-- [4..4] Input from STDIN
-	- `4` get a single ASCII character from STDIN and store it in register A
+- [4..5] Input from STDIN
+	- `4` get a single ASCII character from STDIN and store it in register A
+	- `5` get a string of a maximum length determined by register B and store it
+	in the address specified by register A. After execution register B will
+	contain the number of characters actually read.