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remove some stuff it doesn't need

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andromeda
2026-03-23 17:39:26 +01:00
parent 75e9c27dda
commit 9a88a859cf
1 changed files with 16 additions and 131 deletions
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147
twasm/asm/main.asm
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@@ -75,6 +75,7 @@ start:
; 0x1000 ; memory address, following byte should be a register
; 0x1000 ; not a register
; - operator tokens followed by the wrong number of arguments
; TODO enforce this in `tokenise`
; 0x004F ; hlt, expects 0 arguments
; 0x0000 ; rax, an argument
; - an undefined token is included, like 0x0051
@@ -92,17 +93,6 @@ assemble:
mov di, [rax * TOKEN_TABLE_ENTRY_SIZE + TOKEN_TABLE_ADDR] ; next tte
push rax
; di = next tte
call get_tte_type
; al = type of token
; on stack:
; rax = number of tokens processed
; rdi = number of tokens in table
cmp al, 0x01 ; check if next tte's type is an operator
je .operator ; if so, handle case of operator
jne .continue_operator ; if not, jump past the case
; di = tte of operator
.operator: ; if next tte's type is an operator:
push rdi
@@ -122,7 +112,9 @@ assemble:
cmp al, 2 ; check if operator has two operands
je .operator_2 ; if so, handle case of two operands
jmp .operator_with_args ; of not, handle case of some operands
jmp .unexpected_token ; TODO actually check operator type or not first
; if get_tte_typed_metadata happens to return 0, 1,
; or 2 on a non-operator, it doesn't get caught
; di = tte of operator
.operator_0:
@@ -138,7 +130,11 @@ assemble:
call .output_byte
pop rdi
jmp .continue
pop rax ; rax = number of tokens processed
pop rdi ; rdi = total number of tokens
inc rax
cmp rax, rdi
jmp .loop
; di = tte of operator
.operator_1:
@@ -327,99 +323,13 @@ assemble:
jge .break
jmp .loop
; di = tte of operator
.operator_with_args:
mov [.pending_operator_num_args], al ; save # args fttb
push rdi
; di = next tte
call get_opcode
; al = opcode
mov [.pending_operator_opcode], al ; save opcode fttb
pop rdi
jmp .continue
.continue_operator:
cmp al, 0x02 ; check if next tte's type is a register
je .register ; if so, handle case of register
jne .continue_register ; if not, jump past the case
; di MUST be a valid register tte
.register: ; if next tte's type is a register:
call .dec_num_args ; because we've found an argument, we need 1 fewer noch
cmp byte [.pending_operator_num_args], 1 ; check if this is 1st of 2 args
je .register_one_of_two ; if so, jump to handler
cmp byte [.pending_operator_num_args], 0 ; check if this is the last arg
je .register_last ; if so, jump to handler
; note: not necessarily the last
; of 2 args, it could also be the
; last of 1
; otherwise, discard the token, reset things, and keep going :/
push rsi
mov rsi, .warn_unexpected_register
call print.warn
pop rsi
call .reset_state
jmp .continue_register
.register_one_of_two: ; if it's the first of 2 arguments:
mov [.first_argument], di ; ax = tte
jmp .continue_register
.register_last: ; if it's the last argument:
; swap so the first argument sits in .first_argument
push rax
mov ax, di
mov di, [.first_argument]
mov [.first_argument], ax
pop rax
cmp di, UNRECOGNISED_TOKEN_ID ; check if the second argument is defined
jne .operator_finalise_2 ; if so, there are 2 arguments
; if not, there is just 1
.operator_finalise_1:
mov di, 0x0000 ; id of rax. reg bits 000b
.operator_finalise_2:
; TODO avoid swapping earlier and now :/
mov cx, di
mov di, [.first_argument]
mov si, cx
mov dl, 11b
call get_ModRM
; al = ModR/M byte
push rax
mov al, [.pending_operator_opcode]
call .output_byte ; output operator's opcode
pop rax
call .output_byte ; output ModR/M byte
call .reset_state ; reset all the state parts of this function
jmp .continue_register
.continue_register:
.continue:
pop rax ; rax = number of tokens processed
pop rdi ; rdi = total number of tokens
inc rax
cmp rax, rdi
jge .break ; at end of table, break
jmp .loop
.break:
ret
; constants
.warn_unexpected_register db "ignoring unexpected register", 0x0A, 0x00
.unexpected_token:
mov rsi, .msg_unexpected_token
call print.error
jmp halt
; procedures
@@ -430,35 +340,10 @@ assemble:
inc edx ; increment address
mov [.next_output_byte], edx ; put output byte's address
ret
.next_output_byte dd OUTPUT_ADDR ; next empty byte in output
; TODO get rid of this sketchy bit of state
; runs dec on .pending_operator_num_args
.dec_num_args:
push rax
mov al, [.pending_operator_num_args]
dec al
mov [.pending_operator_num_args], al
pop rax
ret
; resets sketchy memory-based state
; TODO put this state in an accumulator or something
.reset_state:
; I don't actually know if these `word` directives are needed
; TODO check that. I think they are, becasue Nasm doesn't record the size
; of labels?
mov word [.pending_operator_opcode], UNRECOGNISED_TOKEN_ID
mov [.pending_operator_num_args], 0x00
mov word [.first_argument], UNRECOGNISED_TOKEN_ID
ret
; state variables
.pending_operator_opcode db 0x00 ; the operator seeking args
.pending_operator_num_args db 0x00 ; # of args it takes
.first_argument dw UNRECOGNISED_TOKEN_ID ; first argument if there are two
.next_output_byte dd OUTPUT_ADDR ; next empty byte in output
.msg_unexpected_token db "unexpected token while assembling, aborting", 0x0A, 0x00
.msg_operator_0 db "operator_0", 0x0A, 0x00
.msg_operator_1 db "operator_1", 0x0A, 0x00
.msg_operator_1_memory_access db "operator_1_memory_access", 0x0A, 0x00