diff options
Diffstat (limited to 'twasm/asm/main.asm')
| -rw-r--r-- | twasm/asm/main.asm | 84 |
1 files changed, 72 insertions, 12 deletions
diff --git a/twasm/asm/main.asm b/twasm/asm/main.asm index 57af625..1dfad3b 100644 --- a/twasm/asm/main.asm +++ b/twasm/asm/main.asm @@ -188,6 +188,63 @@ get_tte_typed_metadata: ret ; ------------------------------------------------------------------------------ +; get_direct_addressing_ModRM +; +; description: +; given 2 register tokens, returns the ModR/M byte in direct addressing +; (mod = 11b) mode +; +; parameters: +; di = token table entry `reg` +; si = token table entry `R/M` +; +; returned: +; al = ModR/M byte +; ------------------------------------------------------------------------------ + +get_direct_addressing_ModRM: + ; TODO something is backwards in this function but I don't see it. If the test + ; suite fails, it's too far gone; rewrite it. + push rdi + push rsi + ; get metadata of reg + call get_tte_typed_metadata + ; al = typed metadata of reg + pop rsi + pop rdi + + mov bl, al ; bl = metadata of reg + + push rdi + push rsi + push rbx + + ; get metadata of R/M + mov di, si + call get_tte_typed_metadata + ; al = typed metadata of R/M + + pop rbx + pop rsi + pop rdi + + mov dl, al + + shr dl, 2 + and dl, 111b ; mask + + shr bl, 2 + and bl, 111b ; mask + shl bl, 3 + + xor eax, eax + or al, 11b << 6 ; mod bits + or al, dl ; reg bits + or al, bl ; R/M bits + and rax, 0xFF ; mask for byte + ret + +; ------------------------------------------------------------------------------ ; tokenising ; ------------------------------------------------------------------------------ @@ -872,30 +929,33 @@ tokens: dw 0x0059 .by_name_5: .by_id: + dw 0x0010 ; eax + db 0x02 ; type: register + db 00000010b ; reg: 000b + ; width: 10b (32 bits) + + dw 0x0000 ; rax + db 0x02 ; type: register + db 00000011b ; reg: 000b + ; width: 11b (64 bits) + + dw 0x0003 ; rdx + db 0x02 ; type: register + db 00001011b ; reg: 010b + ; width: 11b (64 bits) + dw 0x0053 ; xor db 0x01 ; type: operator db 0x02 ; # operands - dw 0x0010 ; eax - db 0x02 ; type: register - db 0x02 ; width: 32 bit - dw 0x0054 ; inc db 0x01 ; type: operator db 0x01 ; # operands - dw 0x0000 ; rax - db 0x02 ; type: register - db 0x03 ; width: 64 bit - dw 0x0056 ; mov db 0x01 ; type: operator db 0x02 ; # operands - dw 0x0003 ; rdx - db 0x02 ; type: register - db 0x03 ; width: 64 bit - dw 0x004F ; hlt db 0x01 ; type: operator db 0x00 ; # operands |