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LOAD_ADDR equ 0x00010000 ; address this program is loaded at
TOKEN_TABLE_ADDR equ 0x00060000 ; address the token table is loaded at
TOKEN_TABLE_SIZE equ 0x1000 ; max length of table
TEST_ARENA_ADDR equ 0x00060000 ; address to run tests at
TEST_ARENA_SIZE equ 0x1000 ; maximum size tests can use
OUTPUT_ADDR equ 0x00070000 ; address of outputed binary
OUTPUT_SIZE equ 0x1000 ; max length of outputed binary
[bits 64]
[org LOAD_ADDR]
start:
mov rsi, msg_welcome
call print
call run_tests
jmp halt
; ------------------------------------------------------------------------------
; tokenising
; ------------------------------------------------------------------------------
; ------------------------------------------------------------------------------
; copy_token
;
; description:
; copies a token from one spot in memory to another
;
; parameters:
; rdi -> start of buffer to be read
; rsi -> start of buffer to be written
;
; returned:
; rax -> last byte read
; rdx -> last byte written
; ------------------------------------------------------------------------------
copy_token:
.loop:
mov al, [rdi] ; check if next char is a space
cmp al, " "
je .break
call copy_byte ; copy the next byte if not
inc rdi ; increment read- and write-pointers
inc rsi
jmp .loop ; and loop again
.break:
mov rax, rdi ; return values
mov rdx, rsi
ret
.msg db "yo loop copy_token", 0x0D, 0x0A, 0x00
; ------------------------------------------------------------------------------
; copy_byte
;
; description:
; copies a byte from one spot in memory to another
;
; parameters:
; rdi -> word to be read
; rsi -> word to be written
;
; returned:
; rax = byte that was read
; ------------------------------------------------------------------------------
copy_byte:
xor rax, rax ; zero out so it returns fine
mov al, [rdi]
mov [rsi], al
ret
; ------------------------------------------------------------------------------
; utilities
; ------------------------------------------------------------------------------
; ------------------------------------------------------------------------------
; print
;
; description:
; prints a null-terminated string
;
; parameters:
; rsi -> start of null-terminated string
; ------------------------------------------------------------------------------
print:
push rdx
mov rdx, 0x3F8
.loop:
mov al, [rsi]
test al, al
jz .done
out dx, al
inc rsi
jmp .loop
.done:
pop rdx
ret
; ------------------------------------------------------------------------------
; halt
;
; description:
; halts the program, silly :)
; ------------------------------------------------------------------------------
halt:
mov rsi, msg_halt
call print
hlt
jmp halt
; ------------------------------------------------------------------------------
; tests
; ------------------------------------------------------------------------------
; ------------------------------------------------------------------------------
; run_tests
;
; description:
; runs all tests
; ------------------------------------------------------------------------------
run_tests:
mov rsi, .msg
call print
call test_copy_byte
call test_copy_token
ret
.msg db "running test suite...", 0x0D, 0x0A, 0x00
; ------------------------------------------------------------------------------
; test_copy_byte
;
; description:
; tests copy_byte's described functionality
; ------------------------------------------------------------------------------
test_copy_byte:
mov rsi, .msg
call print
mov rdi, test_byte ; byte to be copied
mov rsi, TEST_ARENA_ADDR ; location of test
call copy_byte
mov cx, [rsi]
and ax, 0xFF ; only compare bottom byte
and cx, 0xFF
cmp ax, cx ; compare returned byte to copied byte
jne .fail
cmp al, [test_byte] ; compare returned byte to expected byte
jne .fail
.pass:
mov rsi, msg_pass
call print
ret
.fail:
mov rsi, msg_fail
call print
ret
.msg db "test_copy_byte...", 0x00
; ------------------------------------------------------------------------------
; test_copy_token
;
; description:
; tests copy_token described functionality
; ------------------------------------------------------------------------------
test_copy_token:
mov rsi, .msg
call print
mov rdi, test_token ; read buffer
mov rsi, TEST_ARENA_ADDR ; write buffer
call copy_token
; check reported final indicies with the expected final indicies
cmp rax, test_token + 8 ; last byte read
jne .fail
cmp rdx, TEST_ARENA_ADDR + 8 ; last byte written
jne .fail
mov rsi, TEST_ARENA_ADDR
mov rcx, [rsi]
cmp rcx, [test_token] ; compare copied token to expected token
jne .fail
.pass:
mov rsi, msg_pass
call print
ret
.fail:
mov rsi, msg_fail
call print
ret
.msg db "test_copy_token...", 0x00
; ------------------------------------------------------------------------------
; data
; ------------------------------------------------------------------------------
msg_welcome db "Welcome to Twasm", 0x0D, 0x0A, 0x00
msg_halt db "halted.", 0x0D, 0x0A, 0x00
msg_pass db "passed.", 0x0D, 0x0A, 0x00
msg_fail db "failed.", 0x0D, 0x0A, 0x00
test_byte db "T"
test_token db "TestTokn " ; followed by space. Quad word
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