commit a33621597c8f071c24b189813d2e23e325f1838f
Author: Henry Wilson <m3henry@googlemail.com>
Date: Sat, 10 Jun 2017 08:26:21 +0100
4 star square
Diffstat:
| A | compile | | | 3 | +++ |
| A | main.s | | | 110 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
2 files changed, 113 insertions(+), 0 deletions(-)
diff --git a/compile b/compile
@@ -0,0 +1,3 @@
+#! /bin/bash
+
+gcc -c main.s && ld main.o && ./a.out
diff --git a/main.s b/main.s
@@ -0,0 +1,110 @@
+ .data
+
+dict:
+ .8byte star
+ .8byte star
+ .8byte cr
+ .8byte star
+ .8byte star
+ .8byte halt
+
+star: .8byte enter
+ .8byte docon
+ .8byte 42
+ .8byte emit
+ .8byte exit
+
+buff: .8byte
+
+stack: .skip 1048576
+
+ .global _start
+
+ .text
+
+ .set TOS, %r15
+ .set SP, %r14
+ .set IP, %r13
+ .set WP, %r12
+
+one: .8byte . + 8
+ mov TOS, (SP)
+ add $8, SP
+ mov $1, TOS
+ jmp next
+
+
+double: .8byte . + 8
+ shl TOS
+ jmp next
+
+dup: .8byte . + 8
+ mov TOS, (SP)
+ add $8, SP
+ jmp next
+
+drop: .8byte . + 8
+_drop: mov (SP), TOS
+ sub $8, SP
+ jmp next
+
+emit: .8byte . + 8
+ movq TOS, buff
+ mov $1, %rax # system call 1 is write
+ mov $1, %rdi # file handle 1 is stdout
+ mov $buff, %rsi # address of string to output
+ mov $1, %rdx # number of bytes
+ syscall
+ jmp _drop
+
+cr: .8byte . + 8
+ call _cr
+ jmp next
+newl: .ascii "\n\r"
+_cr:
+ mov $1, %rax # system call 1 is write
+ mov $1, %rdi # file handle 1 is stdout
+ mov $newl, %rsi # address of string to output
+ mov $2, %rdx # number of bytes
+ syscall
+ ret
+
+halt: .8byte . + 8
+ call _cr
+ xor %rdi, %rdi # default return code 0
+ sub $stack, SP
+ jz _halt
+ mov TOS, %rdi
+_halt: mov $60, %rax # system call 60 is exit
+ syscall
+
+exit: .8byte . + 8
+ pop IP
+ jmp next
+
+
+
+_start:
+ mov $stack, SP
+ mov $dict, IP
+next:
+ mov (IP), WP
+ add $8, IP
+ jmp *(WP)
+
+enter:
+ push IP
+ mov WP, IP
+ add $8, IP
+ jmp next
+
+execute: # not done!
+ mov TOS, WP
+ jmp _drop
+
+docon: .8byte . + 8
+ mov TOS, (SP)
+ add $8, SP
+ mov (IP), TOS
+ add $8, IP
+ jmp next
