fix fatal bug in data, get prefix down, start work on awaiting_label, add debug function, more

2 files changed, 165 insertions, 36 deletions

diff --git a/twasm/README.md b/twasm/README.md
index 6509be7..8d0ce3b 100644
--- a/twasm/README.md
+++ b/twasm/README.md
@@ -95,15 +95,15 @@ label definitions are stored and recalled from this table. The memory addresses
 
 ```
 16 bytes
-+---------+
-| 127  64 |
-+---------+
-| address |
-+---------+
-| 63    0 |
-+---------+
-| hash    |
-+---------+
++----------+---------+
+| 127   96 | 95   64 |
++----------+---------+
+| reserved | address |
++----------+---------+
+| 63               0 |
++--------------------+
+| hash               |
++--------------------+
 ```
 
 #### awaiting label table (ALT)
@@ -113,7 +113,7 @@ forward references are stored in this table to be filled in after assembly is ot
 ```
 16 bytes
 +----------+----------+------------------+---------+
-| 127  105 | 104  104 | 103           96 | 95   64 |
+| 127  101 |      100 | 99            96 | 95   64 |
 +----------+----------+------------------+---------+
 | reserved | abs flag | # bytes reserved | address |
 +----------+----------+------------------+---------+
@@ -263,7 +263,7 @@ entries are as follows:
 | 63    56 | 55         48 | 47         40 | 39            32 |
 +----------+---------------+---------------+------------------+
 | opcode   | opcode        | opcode        | opcode           |
-| dst=rel8 | dest=rel      | dst=imm8      | dst=imm          |
+| dst=rel8 | dst=rel       | dst=imm8      | dst=imm          |
 +----------+---------------+---------------+------------------+
 | 31    24 | 23         16 | 15                             0 |
 +----------+---------------+----------------------------------+
@@ -319,7 +319,8 @@ rel  ; rel 16/32
 rel8 ; rel 8
 
 opX&8 ; low 8 bits are the operator flag that goes with opcode at offset X from
-      ; the first opcode in the table entry
+      ; the first opcode in the table entry. High bit is (somewhat confusingly)
+      ; a flag for whether or not the operator comes with an `0F` prefix
 ```
 
 note much room to expand. If an opcode doesn't exist, it should be 0x00
@@ -431,8 +432,7 @@ supported tokens are listed below
 | db    | 0x0100 | pseudo-operator |
 |       | 0x10XX | some memory address; `XX` is as specified below |
 |       | 0x20XX | some constant; `XX` is as specified below |
-|       | 0x3XXX | some label definition; `XXX` is its entry index in the label table |
-|       | 0x4XXX | some label reference; `XXX` is its entry index in the label table
+|       | 0x3XXX | some label; `XXX` is its entry index in the label table |
 |       | 0xFEXX | used to pass some raw value `XX` in place of a token id to a couple of functions that mention this as a feature. If the function doesn't mention it, it will lead to undefined behaviour |
 |       | 0xFFFF | unrecognised token |
 
diff --git a/twasm/asm/main.asm b/twasm/asm/main.asm
index 7f09981..aec5199 100644
--- a/twasm/asm/main.asm
+++ b/twasm/asm/main.asm
@@ -112,16 +112,23 @@ assemble:
 
     jmp .unexpected_token ; otherwise, fail
 
+    dq 0,0,0 ; TODO figure out why this does anything and fix it :shrug:
   .label:
     push rsi
     mov rsi, .msg_label
     call print.debug
     pop rsi
+    mov esi, [.next_output_byte]
+    sub esi, OUTPUT_ADDR ; esi = relative address of label to start of program
+    and edi, 0xFFF       ; edi = index to add address hash to
+    call add_label_address
     jmp .loop_next_token
   .operator:
+    push rdi
     ; di = tte of operator
     call get_tte_typed_metadata 
     ; al = tte typed metadata
+    pop rdi ; di = tte of operator
 
     cmp al, UNRECOGNISED_ID_METADATA ; make sure token has metadata on record
     je .unexpected_token             ; if not, fail
@@ -144,8 +151,9 @@ assemble:
     call print.debug
     pop rsi
 
-                ; di = tte of operator
-    mov sil, 0b ; opcode
+                 ; di = tte of operator
+    mov sil, 0b  ; opcode
+    xor ebx, ebx ; no flags
     call get_opcode
     ; al = opcode
     ; dl = 0x00
@@ -158,18 +166,45 @@ assemble:
     call print.debug
     pop rsi
 
-                ; di = tte of operator
-    mov sil, 0b ; dst=r/m
+    push rdi
+    call .next_token
+    jge .break
+    call .get_next_tte
+    mov rcx, rdi ; cx = operand tte
+    pop rdi
+    push rcx
+
+
+                 ; di = tte of operator
+    mov sil, 0   ; dst=r/m
+    xor ebx, ebx ; no flags
+
+    shr ecx, 12
+    and ecx, 0xF
+    cmp ecx, 0x3
+    je .operator_1_get_opcode_label
+
+    jmp .operator_1_get_opcode_continue
+  .operator_1_get_opcode_label:
+    mov sil, 4 ; dst=rel
+  .operator_1_get_opcode_continue:
     call get_opcode
     ; al = opcode
     ; dl = op flag
     push rdx
+    and dl, 1000b
+    cmp dl, 1000b
+    jne .operator_1_write_prefix_continue
+  .operator_1_write_prefix
+    push rax
+    mov al, 0x0F
+    call .write_byte
+    pop rax ; al = opcode
+  .operator_1_write_prefix_continue
     call .write_byte
     pop rdx ; dl = op flag
 
-    call .next_token
-    jge .break
-    call .get_next_tte
+    pop rdi ; di = next tte
 
     push rdi
     and di, 0xFF00
@@ -177,15 +212,20 @@ assemble:
     pop rdi        ; di = next tte
     je .operator_1_memory
 
+    push rdi
     push rdx
     ; di = next tte
     call get_tte_type
     ; al = type of token
     pop rdx ; dl = op flag
+    pop rdi ; di = next tte
 
     cmp al, 0x02 ; type: register
     je .operator_1_register
 
+    cmp al, 0x04 ; type: label reference
+    je .operator_1_label
+
     jmp .unexpected_token
   .operator_1_memory:
     push rsi
@@ -227,14 +267,35 @@ assemble:
   .operator_1_register_no_prefix:
     mov si, di     ; si = `R/M` tte
     and edx, 0xFF
-    or edx, 0xFE00  ; pass di as direct value
-    mov edi, edx     ; di = op flag
-    mov edx, 11b    ; dl = mod bits
+    or edx, 0xFE00 ; pass di as direct value
+    mov edi, edx   ; di = op flag
+    mov edx, 11b   ; dl = mod bits
     call get_ModRM
     ; al = Mod R/M byte
     call .write_byte
 
     jmp .loop_next_token
+  .operator_1_label:
+    push rsi
+    mov rsi, .msg_operator_1_label
+    call print.debug
+    pop rsi
+
+    mov esi, [.next_output_byte]
+    sub esi, OUTPUT_ADDR ; esi = relative address of label reference to start
+                         ;       of program
+    mov eax, 0x04        ; al = first 4 bits: # bytes reserved
+                         ;      5th bit:      abs flag
+    and edi, 0xFFF       ; edi = index of hash
+    call add_awaiting_label
+
+    mov al, 0xFF     ; reserve space
+    call .write_byte
+    call .write_byte
+    call .write_byte
+    call .write_byte
+
+    jmp .loop_next_token
   .operator_2:
     push rsi
     mov rsi, .msg_operator_2
@@ -274,6 +335,7 @@ assemble:
 
     mov edi, ecx ; di = tte of operator
     xor esi, esi ; dst=r/m; src=r
+    xor ebx, ebx ; no flags
     call get_opcode
     ; al = opcode
     ; dl = op flag
@@ -435,7 +497,7 @@ assemble:
     push rsi
     mov di, cx ; di = tte of operator
     mov sil, 1 ; dst = reg
-    mov bl, 1  ; bl = operator flag byte
+               ; bl = operator flag byte
     call get_opcode
     ; al = opcode
     ; dl = op flag
@@ -614,7 +676,6 @@ assemble:
     mov di, cx ; di = tte of operator
     mov sil, 2 ; dst=r/m,src=imm
                ; bl = operator flag byte
-               ; TODO change sil based on whether bl is 8 bit or not
     push rbx
     and ebx, 1
     cmp bl, 1  ; bit8 flag
@@ -629,7 +690,14 @@ assemble:
     ; dl = op flag
     ; TODO do something if the op flag is present
     call .write_byte
-    pop rsi ; si = tte
+    mov edi, edx ; si = op flag
+    and edi, 0xFF
+    or edi, 0xFE00
+    pop rsi      ; si = r/m; dst tte
+    mov edx, 11b ; dl = mod bits
+    call get_ModRM
+    ; al = Mod R/M byte
+    call .write_byte
 
     call .next_token
     jge .break
@@ -834,6 +902,7 @@ assemble:
   .msg_operator_1 db "operator_1", 0x0A, 0x00
   .msg_operator_1_memory db "operator_1_memory", 0x0A, 0x00
   .msg_operator_1_register db "operator_1_register", 0x0A, 0x00
+  .msg_operator_1_label db "operator_1_label", 0x0A, 0x00
   .msg_operator_2 db "operator_2", 0x0A, 0x00
   .msg_operator_2_memory db "operator_2_memory", 0x0A, 0x00
   .msg_operator_2_memory_register db "operator_2_memory_register", 0x0A, 0x00
@@ -1014,7 +1083,9 @@ get_ModRM:
 ;
 ; returned:
 ; al = opcode; the rest of rax is zeroed.
-; dl = lower 3 bits: op flag, if applicable. The rest of rdx is zeroed.
+; dl = lower 3 bits: op flag, if applicable.
+;      4th bit:      0x0F prefix flag
+;      the rest of rdx is zeroed.
 ; ------------------------------------------------------------------------------
 
 get_opcode:
@@ -1112,6 +1183,7 @@ get_reg_bits:
 ; rax = number of tokens processed
 ; ------------------------------------------------------------------------------
 
+align 16 ; idk, fixes some alignment bug sometimes :/
 tokenise:
                ; rdi -> current byte of program
   add rsi, rdi ; rsi -> last byte of program
@@ -1953,6 +2025,25 @@ print:
   .warn_msg db 0x1B, "[1;35m", "[WARN]: ", 0x1B, "[0m", 0x00
 
 ; ------------------------------------------------------------------------------
+; print_least_4_bits
+;
+; description:
+; prints the least significant 4 bits of rax for debugging reasons
+; ------------------------------------------------------------------------------
+
+print_least_4_bits:
+  push rax
+  push rsi
+  add eax, 0x30
+  mov [.byte], al
+  mov rsi, .byte
+  call print.warn
+  pop rsi
+  pop rax
+  ret
+  .byte db 0x00, 0x0A, 0x00
+
+; ------------------------------------------------------------------------------
 ; halt
 ;
 ; description:
@@ -2123,7 +2214,7 @@ add_label_hash:
 ;
 ; parameters
 ; rdi = lower 3 bytes: index of label table to add the address to
-; rsi = 64-bit address to be added, relative to start of program
+; esi = 32-bit address to be added, relative to start of program
 ;
 ; returned
 ; rax = return value: 0 = success
@@ -2133,10 +2224,10 @@ add_label_hash:
 add_label_address:
   and edi, 0xFFF
   shl rdi, 4 ; rdi * 16
-  mov rax, [LABEL_TABLE_ADDR + rdi]
-  cmp rax, 0
+  mov eax, [LABEL_TABLE_ADDR + 8 + rdi]
+  cmp eax, 0
   jne .ret_1
-  mov [LABEL_TABLE_ADDR + 16 + rdi], rsi
+  mov [LABEL_TABLE_ADDR + 8 + rdi], esi
   xor eax, eax
   ret
   .ret_1:
@@ -2144,6 +2235,42 @@ add_label_address:
     ret
 
 ; ------------------------------------------------------------------------------
+; add_awaiting_label
+;
+; description:
+; adds metadata of a forward reference to be completed in a later pass
+;
+; parameters
+; rdi = lower 3 bytes: index of label table this forward reference is awaiting
+; esi = 32-bit address of reference, relative to start of program
+; al = lower 4 bytes: # bytes reserved at [OUTPUT_ADDR + esi] for the reference
+;      byte 5:        abs flag if the reference is absolute
+; ------------------------------------------------------------------------------
+
+add_awaiting_label:
+  and edi, 0xFFF
+  and esi, esi
+  and eax, 0x1F
+  push rax
+  xor eax, eax
+  .loop:
+    cmp rax, AWAITING_LABEL_TABLE_SIZE
+    jge .break
+    mov rcx, [AWAITING_LABEL_TABLE_SIZE + rax]
+    cmp rcx, 0 ; empty slot
+    je .break
+    add rax, 16
+    jmp .loop
+  .break:
+    pop rcx ; cl = bits passed to al
+    shl rdi, 4
+    mov rdx, [LABEL_TABLE_ADDR + rdi]
+    mov [AWAITING_LABEL_TABLE_ADDR + rax], rdx ; hash
+    mov [AWAITING_LABEL_TABLE_ADDR + 8 + rax], esi ; address
+    mov [AWAITING_LABEL_TABLE_ADDR + 13 + rax], cl ; bits passed to al
+    ret
+
+; ------------------------------------------------------------------------------
 ; clear_token_table
 ;
 ; description:
@@ -2818,6 +2945,8 @@ opcodes:
                   ; 00:
                   ; 01: bit8 flag
 
+    dd 0x00000000
+
     ; jmp
     dw 0x005C
     db 0xFF   ; r/m
@@ -2840,12 +2969,12 @@ opcodes:
     dw 0x0000
 
     dw 0x0000
-    db 0x00       ; TODO figure out the 0x0F prefix this will need
+    db 0x84       ; rel16/32
     db 0x74       ; rel8
 
-    dd 0x00000000 ; 00000:
-                  ; 0:     rel8
-                  ; 00:
+    dd 0x00080000 ; 0000:
+                  ; 8:    rel16/32 0x0F flag
+                  ; 000:
 
     dd 0x00000000