commit 556b58f8f77a2633e20aed7dcb7972a0d6cbe5a4
parent 027701095b691b156250deaf72804bfa791fe63b
Author: Henry Wilson <m3henry@googlemail.com>
Date: Wed, 21 Jun 2017 02:50:52 +0100
rudimentary catch stack underflow
Diffstat:
| M | main.s | | | 38 | ++++++++++++++++++++++++++++++++------ |
1 file changed, 32 insertions(+), 6 deletions(-)
diff --git a/main.s b/main.s
@@ -3,17 +3,20 @@
.data
verb forth COLD "COLD" end
-_cold: saycr "aFORTH alpha \xe2\x9c\x93"
+_cold: do RESETDATA
+ saycr "aFORTH alpha ✓"
set numtib 0
- do ABORT
+ do QUIT
verb forth ABORT
+ do RESETDATA
do QUIT
verb forth QUIT
+# do RESETRETURN
2: do TIB
const 80
- say "? "
+ say "➤ "
do ACCEPT
test equal 0 1f
set numtib
@@ -38,6 +41,11 @@ verb forth INTERPRET
do drop2
test greater 0 2f
do DROP
+ do PAD
+ say "Unknown token: "
+ do PRINT
+ do CR
+ do ABORT
goto 2f
1: do EXECUTE
2: get numin
@@ -320,6 +328,8 @@ verb forth mod "%"
do DROP
endword
+rspbk: .quad 0
+
buff: .quad 0
stack: .skip 1024 #1048576
@@ -346,9 +356,16 @@ stack: .skip 1024 #1048576
.set ARGE, %r8
.set ARGF, %r9
-
# Stack manipulation
+verb code RESETDATA
+ mov $stack, SP
+ jmp next
+
+verb code RESETRETURN
+ mov rspbk, %rsp
+ jmp next
+
verb code DUP
_dup
jmp next
@@ -362,8 +379,16 @@ _drop2: retreat SP
verb code DROP
_drop: mov (SP), TOS
retreat SP
+ cmp $stack, SP
+ jge next # normal operation
+ mov $1f, IP
jmp next
+1: do RESETDATA
+ do CR
+ saycr "Stack underflow!"
+ do QUIT
+
verb code SWAP
push TOS
mov (SP), TOS
@@ -405,7 +430,7 @@ verb code TYPE
jmp _drop2
verb code HALT
- xor ARGA, ARGA # default return code 0
+_halt: xor ARGA, ARGA # default return code 0
sub $stack, SP
jz 1f
mov TOS, ARGA
@@ -625,7 +650,8 @@ verb code EXECUTE
.text
-_start: mov $stack, SP
+_start: #mov $stack, SP
+ movq %rsp, rspbk
mov $_cold, IP
next:
mov (IP), WP
