+;; vim: syntax=fasm
+
format ELF64 executable
+;; "Syscalls" {{{
+
+;; [NOTE] Volatile registers Linux (syscalls) vs UEFI
+;;
+;; Linux syscalls: RAX, RCX, R11
+;; UEFI: RAX, RCX, R11, RDX, R8, R9, R10
+
+;; We are in the process of replacing our dependency on Linux with a dependency
+;; on UEFI. The following macros attempt to isolate what would be syscalls in
+;; Linux; thus, we will be able to replace these with UEFI-based implementations,
+;; and in theory we should expect the program to work.
+
+;; Print a string of a given length.
+;;
+;; Input:
+;; - RCX = Pointer to buffer
+;; - RDX = Buffer length
+;;
+;; Clobbers: RAX, RCX, R11, RDI, RSI
+macro sys_print_string {
+ mov rax, 1
+ mov rdi, 1
+ mov rsi, rcx
+ syscall
+}
+
+;; }}}
+
;; The code in this macro is placed at the end of each Forth word. When we are
;; executing a definition, this code is what causes execution to resume at the
;; next word in that definition.
forth_asm EMIT, 'EMIT'
pushr rsi
pushr rax
- mov rax, 1
- mov rdi, 1
- lea rsi, [rsp]
+
+ lea rcx, [rsp]
mov rdx, 1
- syscall
+ sys_print_string
+
add rsp, 8
popr rax
popr rsi
;; Takes a string on the stack and replaces it with the decimal number that the
;; string represents.
forth_asm PARSE_NUMBER, 'PARSE-NUMBER'
- pop [parse_number.length] ; Length
- pop [parse_number.buffer] ; String pointer
+ pop rcx ; Length
+ pop rdi ; String pointer
push rsi
call parse_number
;; Takes a string (in the form of a pointer and a length on the stack) and
;; prints it to standard output.
forth_asm TELL, 'TELL'
- mov rbx, rsi
- mov rcx, rax
+ pushr rax
+ pushr rsi
- mov rax, 1
- mov rdi, 1
- pop rdx ; Length
- pop rsi ; Buffer
- syscall
+ pop rdx ; Length
+ pop rcx ; Buffer
+ sys_print_string
- mov rax, rcx
- mov rsi, rbx
+ popr rsi
+ popr rax
next
;; Exit the program cleanly.
mov rdi, 0
syscall
-forth HELLO, 'HELLO'
- dq LIT, 'H', EMIT
- dq LIT, 'e', EMIT
- dq LIT, 'l', EMIT
- dq LIT, 'l', EMIT
- dq LIT, 'o', EMIT
- dq LIT, '!', EMIT
- dq NEWLINE
- dq EXIT
-
;; Duplicate a pair of elements.
forth_asm PAIRDUP, '2DUP'
pop rbx
;; Stack is (word length word length).
dq FIND ; Try to find word
dq DUP_
- dq ZBRANCH, 8 * 20 ; Check if word is found
+ dq ZBRANCH, 8 * 22 ; Check if word is found
;; - Word is found -
- dq STATE, GET, ZBRANCH, 8 * 9 ; Check whether we are in compilation or immediate mode
+ dq STATE, GET, ZBRANCH, 8 * 11 ; Check whether we are in compilation or immediate mode
;; (Word found, compilation mode)
- dq DUP_, IS_IMMEDIATE, NOT_, ZBRANCH, 8 * 4 ; If the word is immediate, continue as we would in immediate mode
+ dq DUP_, IS_IMMEDIATE, NOT_, ZBRANCH, 8 * 6 ; If the word is immediate, continue as we would in immediate mode
;; Otherwise, we want to compile this word
dq TCFA
dq COMMA
+ dq DROP, DROP
dq EXIT
;; (Word found, immediate mode)
loop .flip
;; Print the buffer
- mov rax, 1
- mov rdi, 1
- mov rsi, .buffer
+ mov rcx, .buffer
mov rdx, [.printed_length]
- syscall
+ sys_print_string
;; Restore RSI and continue execution
pop rsi
dq LIT, 1, STATE, PUT_BYTE
dq EXIT
+forth_asm TICK, "'"
+ lodsq
+ push rax
+ next
+
+forth_asm ROT, 'ROT'
+ pop rax
+ pop rbx
+ pop rdx
+ push rax
+ push rdx
+ push rbx
+ next
+
+forth_asm PICK, 'PICK'
+ pop rax
+ lea rax, [rsp + 8 * rax]
+ mov rax, [rax]
+ push rax
+ next
+
+forth_asm EQL, '='
+ pop rax
+ pop rbx
+ cmp rax, rbx
+ je .eq
+.noteq:
+ push 0
+ next
+.eq:
+ push 1
+ next
+
forth MAIN, 'MAIN'
- dq HELLO
dq INTERPRET
dq BRANCH, -8 * 2
dq TERMINATE
;; Reserve space for compiled words, accessed through HERE.
here dq here_top
-here_top rq $2000
+here_top rq $4000
;; Return stack
rq $2000
projects / rrq / jonasforth.git / blobdiff