no mod r/m flag on 'out' opcode, use r/m<-r as default r<-r

twasm/asm/main.asm

@@ -112,7 +112,6 @@ 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
@@ -479,9 +478,15 @@ assemble:
     pop rdi        ; di = next tte
     je .operator_2_register_const
 
+    push rcx
+    push rdi
+    push rsi
     ; di = next tte
     call get_tte_type
     ; al = type of token
+    pop rsi ; si = dst tte
+    pop rdi ; di = src tte
+    pop rcx ; cx = operator tte
 
     cmp al, 0x02                     ; check if token is a register
     je .operator_2_register_register ; if so, handle
@@ -551,19 +556,20 @@ assemble:
     push rdi
     push rsi
     mov di, cx ; di = tte of operator
-    mov sil, 1 ; dst = reg
+    mov sil, 0 ; dst = r/m
                ; bl = operator flag byte
     call get_opcode
     ; al = opcode
-    ; dl = op flag
+    ; dl = flags
-    ; TODO do something if the op flag is present
     call .write_byte
     pop rsi ; si = tte
     pop rdi ; di = tte
 
+    push rdx
     ; di = tte
     call get_tte_typed_metadata
     ; al = register typed metadata
+    pop rdx ; dl = flags
     and al, 11b ; al = register width
 
     cmp al, 00b          ; 8 bit
@@ -581,10 +587,12 @@ assemble:
     ; 16 bit
     push rdi
     push rsi
+    push rdx
     mov edi, .buffer_end - .buffer ; length of buffer
     mov rsi, .buffer               ; buffer location
     mov dl, 0x66
     call elemb
+    pop rdx ; dl = flags
     pop rsi ; si = src tte
     pop rdi ; di = dst tte
     cmp al, 1
@@ -593,10 +601,12 @@ assemble:
     ; 64 bit
     push rdi
     push rsi
+    push rdx
     mov edi, .buffer_end - .buffer ; length of buffer
     mov rsi, .buffer               ; buffer location
     mov dl, 0x48
     call elemb
+    pop rdx ; dl = flags
     pop rsi ; si = src tte
     pop rdi ; di = dst tte
     cmp al, 0
@@ -607,10 +617,12 @@ assemble:
     ; 16 bit
     push rdi
     push rsi
+    push rdx
     mov edi, .buffer_end - .buffer ; length of buffer
     mov rsi, .buffer               ; buffer location
     mov dl, 0x66
     call elemb
+    pop rdx ; dl = flags
     pop rsi ; si = src tte
     pop rdi ; di = dst tte
     cmp al, 0
@@ -619,10 +631,12 @@ assemble:
     ; 64 bit
     push rdi
     push rsi
+    push rdx
     mov edi, .buffer_end - .buffer ; length of buffer
     mov rsi, .buffer               ; buffer location
     mov dl, 0x48
     call elemb
+    pop rdx ; dl = flags
     pop rsi ; si = src tte
     pop rdi ; di = dst tte
     cmp al, 0
@@ -633,10 +647,12 @@ assemble:
     ; 16 bit
     push rdi
     push rsi
+    push rdx
     mov edi, .buffer_end - .buffer ; length of buffer
     mov rsi, .buffer               ; buffer location
     mov dl, 0x66
     call elemb
+    pop rdx ; dl = flags
     pop rsi ; si = src tte
     pop rdi ; di = dst tte
     cmp al, 0
@@ -645,10 +661,12 @@ assemble:
     ; 64 bit
     push rdi
     push rsi
+    push rdx
     mov edi, .buffer_end - .buffer ; length of buffer
     mov rsi, .buffer               ; buffer location
     mov dl, 0x48
     call elemb
+    pop rdx ; dl = flags
     pop rsi ; si = src tte
     pop rdi ; di = dst tte
     cmp al, 1
@@ -656,14 +674,17 @@ assemble:
 
     jmp .operator_2_register_register_continue
   .operator_2_register_register_continue:
-    push rsi
+    shr dl, 4
-    mov esi, edi ; si = reg; src tte
+    and dl, 1
-    pop rdi      ; di = r/m; dst tte
+    cmp dl, 1
+    je .operator_2_register_register_continue_no_ModRM
+                 ; si = reg; src tte
+                 ; di = r/m; dst tte
     mov edx, 11b ; dl = mod bits
     call get_ModRM
     ; al = Mod R/M byte
     call .write_byte
-
+  .operator_2_register_register_continue_no_ModRM:
     jmp .loop_next_token
   .operator_2_register_const:
     push rsi
@@ -1083,7 +1104,15 @@ get_ModRM:
 ;
 ; returned:
 ; al = opcode; the rest of rax is zeroed.
-; dl = flags
+; dl = flagsX
+; +----------------------------------------------------+
+; | flagsX byte                                        |
+; +----------+-----------+-------------+---------------+
+; | 7      5 |     4     |      3      | 2           0 |
+; +----------+-----------+-------------+---------------+
+; | reserved | no ModR/M | 0x0F prefix | operator flag |
+; +----------+-----------+-------------+---------------+
+;
 ; ------------------------------------------------------------------------------
 
 get_opcode:
@@ -1172,7 +1201,6 @@ 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
@@ -2768,16 +2796,22 @@ opcodes:
     dw 0x004F
     db 0xF4       ; opcode
     db 0x00       ; reserved
+
     dd 0x00000000
+
     dd 0x00000000
+
     dd 0x00000000
 
     ; int3
     dw 0x0050
     db 0xCC       ; opcode
     db 0x00       ; reserved
+
     dd 0x00000000
+
     dd 0x00000000
+
     dd 0x00000000
 
     ; xor
@@ -2799,8 +2833,11 @@ opcodes:
     dw 0x0054
     db 0xFF       ; r/m
     db 0x00
+
     dd 0x00000000
+
     dd 0x00000000
+
     dd 0x00000000
 
     ; dec
@@ -2826,6 +2863,7 @@ opcodes:
     dw 0x0000
 
     dd 0x00000000
+
     dd 0x00000000
 
     ; mov bit8
@@ -2853,6 +2891,7 @@ opcodes:
     dw 0x0000
 
     dd 0x00000000
+
     dd 0x00000000
 
     ; sub
@@ -2889,8 +2928,11 @@ opcodes:
     dw 0x005A
     db 0xC3       ; opcode
     db 0x00       ; reserved
+
     dd 0x00000000
+
     dd 0x00000000
+
     dd 0x00000000
 
     ; cmp
@@ -2989,17 +3031,25 @@ opcodes:
     dw 0x0060
     db 0x8F       ; r/m
     db 0x00
+
     dd 0x00000000
+
     dd 0x00000000
+
     dd 0x00000000
 
     ; out
     ; TODO enforce DX AL requirement, ignore ModR/M correctly
     dw 0x0061
-    db 0xEE
+    db 0xEE       ; r/m <- r
     db 0x00
+
     dd 0x00000000
-    dd 0x00000000
+
+    db 0x10       ; 10: no ModRM flag
+    db 0x00
+    dw 0x0000
+
     dd 0x00000000
   .by_id_end:
 

twasm/package.nix

@@ -14,8 +14,7 @@ stdenv.mkDerivation {
       asm/main.asm \
       -o out.bin \
       -w+all \
-      -w-reloc-abs \
+      -w-reloc-abs
-      -O0
   '';
   installPhase = ''
     dd if=/dev/zero of=disk bs=512 count=2880