commit 502266a55c00d8e56637f58e990c030a0158d110
parent fd2034c2bb35c5a237c1b9ac1763daa9b8a89363
Author: Christian Ermann <christianermann@gmail.com>
Date: Fri, 1 Nov 2024 12:17:28 -0700
Add 'postpone', 'if', and 'while'
Diffstat:
2 files changed, 37 insertions(+), 2 deletions(-)
diff --git a/forth.f b/forth.f
@@ -1,3 +1,15 @@
: test type ;
+: ahead here 0 , ;
+: if postpone ?branch ahead ; immediate
+: then here swap ! ; immediate
+: else postpone branch ahead swap postpone then ; immediate
+
+: begin here ; immediate
+: while postpone if swap ; immediate
+: again postpone branch comma ; immediate
+: repeat postpone again postpone then ; immediate
+
+: test-if if type then exit ;
+
diff --git a/forth.s b/forth.s
@@ -575,7 +575,13 @@ defcode "+", 1, 0, 0xC4ADC675, plus, two_dup
push w
next
-defcode "aligned", 7, 0, 0xC73174DF, aligned, plus
+defcode "or", 2, 0, 0x5D342984, or_, plus
+ pop w
+ pop x
+ or w, w, x
+ push w
+
+defcode "aligned", 7, 0, 0xC73174DF, aligned, or_
pop w
addi w, w, 3
andi w, w, 0xFFFFFFFC
@@ -686,6 +692,23 @@ defcode "immediate?", 10, 0, 0x89F23E9F, immediate_q, compiling_q
push w
next
+defword "postpone", 8, flag_immediate, 0x933F531F, postpone, immediate_q
+ .int parse_word, find # TODO: was word actually found?
+ .int to_cfa, dup
+ .int immediate_q, q_branch, _postpone_compile
+_postpone_execute:
+ # stores "<xt>" into the current definition
+ .int comma, exit
+_postpone_compile:
+ # stores "lit <xt> ," into the current definition
+ .int lit, lit, comma, comma, lit, comma, comma, exit
+
+defword "immediate", 9, 0, 0xF232267A, immediate, postpone
+ .int latest, fetch, lit, flag_offset, plus, dup
+ .int fetch, lit, flag_immediate, or_
+ .int swap, store
+ .int exit
+
.section ".text"
file_get_char:
la w, _bootstrap
@@ -723,7 +746,7 @@ version_string:
word_buffer: .space 255
.balign cell
-_latest: .int name_immediate_q
+_latest: .int name_immediate
_here: .int __here_start
_meta: .int __meta_start
