Add extern funcs, parameter registers, fix asm_rm RSP bug

1 files changed, 30 insertions, 12 deletions

diff --git a/doc/Documentation.md b/doc/Documentation.md
index 3f9bd1a..a046057 100644
--- a/doc/Documentation.md
+++ b/doc/Documentation.md
@@ -1,22 +1,25 @@
 # Opcode
-Variable length opcodes. Sizes range from 1 to 4 bytes.
+Variable length opcodes. Sizes range from 1 to 5 bytes.
 ## Instruction formats
 Instructions can be in 7 different formats:
 1. 1 byte: Opcode(u8)
-2. 2 bytes: Opcode(u8) + register(u8)
-3. 3 bytes: Opcode(u8) + register(u8) + register(u8)
+2. 2 bytes: Opcode(u8) + register(i8)
+3. 3 bytes: Opcode(u8) + register(i8) + register(i8)
 4. 3 bytes:\
 4.1 Opcode(u8) + intermediate(u16)\
 4.2 Opcode(u8) + data(u16)\
 4.3 Opcode(u8) + offset(i16)\
-4.4 Opcode(u8) + num_reg(u16)\
-4.5 Opcode(u8) + register(u8) + num_args(u8)
-5. 4 bytes: Opcode(u8) + register(u8) + register(u8) + register(u8)
+4.4 Opcode(u8) + register(i8) + num_args(u8)
+5. 4 bytes: Opcode(u8) + register(i8) + register(i8) + register(i8)
 6. 4 bytes:\
-6.1 Opcode(u8) + register(u8) + offset(i16)\
-6.2 Opcode(u8) + register(u8) + intermediate(u16)\
-6.3 Opcode(u8) + register(u8) + data(u16)
-7. 4 bytes: Opcode(u8) + index(u16) + num_args(u8)
+6.1 Opcode(u8) + register(i8) + offset(i16)\
+6.2 Opcode(u8) + register(i8) + intermediate(u16)\
+6.3 Opcode(u8) + register(i8) + data(u16)\
+6.4 Opcode(u8) + num_param_reg(u8) + num_local_var_reg(u16)
+7. 5 bytes: Opcode(u8) + index(u16) + num_args(u8) + register(i8)
+## Registers
+Registers have a range of 128. Local variables start from register 0 and increment while parameters start from -1
+and decrement.
 
 # Compiler flow
 (Tokenize&parse -> Resolve AST -> Generate SSA -> Generate bytecode) -> Generate program\
@@ -26,7 +29,7 @@ and writing it to a file, which is an IO bottlenecked operation and it won't ben
 and may even lose performance because of it.
 
 # Bytecode
-The layout of the full bytecode is: Header (Intermediates Strings Functions Instructions)*
+The layout of the full bytecode is: Header (Intermediates Strings Functions External_Functions Instructions)*
 
 # Bytecode header
 ## Header layout
@@ -63,7 +66,7 @@ The versions in the header only changes for every release, not every change.
 ## String
 |Type|Field|Description                                                                            |
 |----|----|----------------------------------------------------------------------------------------|
-|u16 |Size|The size of the string, in bytes.                                                       |
+|u16 |Size|The size of the string, in bytes. Excluding the null-terminate character.               |
 |u8* |Data|The data of the string, where the size is defined by @Size. Strings are null-terminated.|
 
 # Bytecode functions
@@ -72,6 +75,21 @@ The versions in the header only changes for every release, not every change.
 |----|-------------------|---------------------------------|
 |u16 |Number of functions|The number of internal functions.|
 
+# Bytecode external functions
+## External functions layout
+|Type              |Field             |Description                                                                              |
+|------------------|------------------|-----------------------------------------------------------------------------------------|
+|u16               |num_extern_func   |The number of external functions.                                                        |
+|u32               |extern_funcs_size |The size of the external functions section, in bytes.                                    |
+|External function*|External functions|Multiple external functions, where the number of functions is defined by @num_extern_func|
+
+## External function
+|Type|Field   |Description                                                                                          |
+|----|--------|-----------------------------------------------------------------------------------------------------|
+|u8  |num_args|The number of arguments the functions has.                                                           |
+|u8  |name_len|The length of the external function name, in bytes. Excluding the null-terminate character.          |
+|u8* |name    |The name of the external function, where the size is defined by @name_len. Names are null-terminated.|
+
 # Bytecode instructions
 ## Instructions layout
 |Type       |Field            |Description                                                                |