From c09a85ef9da7c1608b9d78c41975b4fdbbadf3e4 Mon Sep 17 00:00:00 2001
From: "Juan J. Martinez" <jjm@usebox.net>
Date: Mon, 22 May 2023 07:13:54 +0100
Subject: Use a bitmap font

---
 game/text.asm | 95 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)
 create mode 100644 game/text.asm

(limited to 'game/text.asm')

diff --git a/game/text.asm b/game/text.asm
new file mode 100644
index 0000000..06a40b3
--- /dev/null
+++ b/game/text.asm
@@ -0,0 +1,95 @@
+;
+; Bitmap font
+;
+
+;
+; Write text on screen
+;
+; Expects a 4x8 font on "font" label.
+;
+; in: a : x: text to write
+;     b, y : (x, y) dst coords
+put_text:
+    push y
+    push b
+
+put_text_loop:
+    ld y, [a : x]
+    cmp y, 0
+    bz
+    jmp put_text_exit
+
+    sub y, 32
+
+    push a
+    push x
+
+    rol y, 5
+    ld x, y
+    and x, 31
+    and y, 224
+
+    ld a, >font
+    add a, x
+
+    ld x, <font
+    add x, y
+    bo
+    inc a
+
+    call put_text_c
+
+    pop x
+    pop a
+
+    inc x
+    bo
+    inc a
+
+    pop b
+    add b, 4
+    push b
+
+    jmp put_text_loop
+
+put_text_exit:
+    pop b
+    pop y
+    ret
+
+put_text_c:
+    ; settings mode
+    ld y, 128
+    ld b, 0xb0
+    port b, y
+
+    ; setup
+    inc b
+
+    ; addr: char sprite
+    ld y, x
+    port b, y
+    ld y, a
+    port b, y
+
+    ; x
+    ld y, [sp + 4]
+    port b, y
+
+    ; y
+    ld y, [sp + 5]
+    port b, y
+
+    ; w
+    ld y, 4
+    port b, y
+    ; h
+    ld y, 8
+    port b, y
+
+    ; blit
+    dec b
+    ; write, transparent
+    ld y, 3
+    port b, y
+    ret
-- 
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