forth-riscv

commit befdb1f165c3f13255de63d0ca7f3a9513ce6673
parent d8269ac8c0f566dbb8fd5e48acaeefa0ef04533e
Author: Christian Ermann <christianermann@gmail.com>
Date:   Mon,  4 Nov 2024 20:21:07 -0800

Add 'parse-char'

Diffstat:
M
forth.s
 | 
31
++++++++++++++++++++++++++++++-

1 file changed, 30 insertions(+), 1 deletion(-)
diff --git a/forth.s b/forth.s
@@ -245,7 +245,36 @@ defcode "fib", 3, 0, 0xBCE49236, fib, tib
     push w
     next
 
-defcode "parse-word", 10, 0, 0xB218226F, parse_word, fib
+defcode "parse-char", 10, 0, 0xDF4F729B, parse_char, fib
+    la w, _source
+    load_cell w, 0(w)
+    la x, _source_len
+    load_cell x, 0(x)
+    la y, _input_offset
+    load_cell y, 0(y)
+    add w, w, y
+    sub x, x, y
+
+    li s3, 0x20 # space
+1:  # find start of word
+    beqz x, 3f     # out of chars? -> stop!
+    lb t0, 0(w)    # next char!
+    addi w, w, 1   # inc. addr
+    addi y, y, 1   # inc. offset
+    addi x, x, -1  # dec. len
+    beq t0, s3, 1b # space? -> skip!
+
+2:  # done
+    la t1, _input_offset
+    store_cell y, 0(t1)
+    push t0
+    next
+
+3: # out of chars
+    mv t0, zero
+    j 2b
+
+defcode "parse-word", 10, 0, 0xB218226F, parse_word, parse_char
     la w, _source
     load_cell w, 0(w) # buff addr
     la x, _source_len