From c78e54e173a92ec5ed2eedb10a5514e2ffcf48c2 Mon Sep 17 00:00:00 2001
From: kitty <nepeta@canaglie.net>
Date: Fri, 20 Mar 2026 15:20:31 +1100
Subject: =?UTF-8?q?rudimentary=20Error=20Technology=E2=84=A2?=
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---
 sanctuary.s | 43 ++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 40 insertions(+), 3 deletions(-)

(limited to 'sanctuary.s')

diff --git a/sanctuary.s b/sanctuary.s
index 0d35337..53749cc 100644
--- a/sanctuary.s
+++ b/sanctuary.s
@@ -1,15 +1,26 @@
 ; sanctuary
 
 ; macros {{{
-; TODO: error handling (once i add that)
+; the error handling feels slow but i dont know a better way
+; todo at some point make these use actual error codes
 %macro pspush 1
 	lea r15, [r15-8]
 	mov qword [r15], %1
+
+	cmp r15, wstk_b
+	jge %%ok
+	call abort
+	%%ok:
 %endmacro
 
 %macro pspop 1
 	mov %1, qword [r15]
 	lea r15, [r15+8]
+
+	cmp r15, wstk
+	jle %%ok
+	call abort
+	%%ok:
 %endmacro
 
 %define s_latest 0
@@ -58,8 +69,8 @@
 %assign init_brk	0x9c400
 
 section .bss
-resq 4091
-wstk: resq 1
+wstk_b:	resq 4091
+wstk:	resq 1
 
 section .text
 global _start
@@ -502,6 +513,16 @@ defcode "char", char, 0
 	pspush r11
 	ret
 
+defcode "(execute)", do_execute, 0
+	pspop r11
+	call r11
+	ret
+
+defcode "execute", execute, 0
+	call to_body
+	call do_execute
+	ret
+
 ; number {{{
 defcode "number", number, 0 ; ( c-addr u -- ?n flag )
 	pspop r11 ; u
@@ -965,6 +986,21 @@ defcode "?branch", q_branch, 0
 	mov qword [here], r12
 	ret
 
+; error handling {{{
+; default error handler, because we don't have QUIT yet
+; it just Exits with exit code 1
+defcode "(0handler)", do_0handler, 0
+	mov rdi, 1
+	mov rax, __NR_exit
+	syscall
+	ret
+
+defcode "abort", abort, 0
+	mov r11, qword [handler]
+	call r11
+	ret
+; }}}
+
 ; TEMPORARY WONKY DEBUGGING FUNCTIONS {{{
 ; .s {{{
 defcode ".s", dots, 0
@@ -1024,6 +1060,7 @@ defvar "dp$", dp$, 0, 0
 defvar "tib", tib, 0, initfile
 defvar "#tib", n_tib, 0, initlen
 defvar ">in", to_in, 0, 0
+defvar "handler", handler, 0, do_0handler
 defvar "latest", latest, 0, lfa_latest
 
 initfile: incbin "sanctuary.fs"
-- 
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