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authorThomas Albers Raviola <thomas@thomaslabs.org>2024-11-21 15:55:03 +0100
committerThomas Albers Raviola <thomas@thomaslabs.org>2024-11-21 15:55:03 +0100
commit6d4ad089c5b758ad8af4f68bf385a26ec4e9653a (patch)
tree2fd65006b57d646b53e121aef42bba5ee5852840 /asm
Initial commit
Diffstat (limited to 'asm')
-rw-r--r--asm/crt0.asm64
-rw-r--r--asm/delay.asm13
-rw-r--r--asm/isr.asm17
3 files changed, 94 insertions, 0 deletions
diff --git a/asm/crt0.asm b/asm/crt0.asm
new file mode 100644
index 0000000..6f92149
--- /dev/null
+++ b/asm/crt0.asm
@@ -0,0 +1,64 @@
+#include <hardware.h>
+
+ .module crt0
+ .globl _main
+
+ .area _HEADER (ABS)
+ .org 0x0000
+start:
+ xor a
+ ld i, a
+ ld sp, #0x0000
+ di
+
+ call gsinit
+ call _main
+1$:
+ halt
+ jr 1$
+
+ ;; Ordering of segments for the linker.
+ .area _HOME
+ .area _CODE
+ .area _INITIALIZER
+ .area _GSINIT
+ .area _GSFINAL
+
+ .area _DATA
+ .area _INITIALIZED
+ .area _BSEG
+ .area _BSS
+ .area _HEAP
+
+ .area _CODE
+
+ .area _GSINIT
+gsinit:
+ ;; Default-initialized global variables.
+ ld bc, #l__DATA
+ ld a, b
+ or a, c
+ jr Z, zeroed_data
+ ld hl, #s__DATA
+ ld (hl), #0x00
+ dec bc
+ ld a, b
+ or a, c
+ jr Z, zeroed_data
+ ld e, l
+ ld d, h
+ inc de
+ ldir
+zeroed_data:
+ ;; Explicitly initialized global variables.
+ ld bc, #l__INITIALIZER
+ ld a, b
+ or a, c
+ jr Z, gsinit_next
+ ld de, #s__INITIALIZED
+ ld hl, #s__INITIALIZER
+ ldir
+
+gsinit_next:
+ .area _GSFINAL
+ ret
diff --git a/asm/delay.asm b/asm/delay.asm
new file mode 100644
index 0000000..f04f046
--- /dev/null
+++ b/asm/delay.asm
@@ -0,0 +1,13 @@
+ .module delay
+
+__delay_ms::
+ ld b, a
+1$:
+ ld hl, #400
+2$:
+ dec hl
+ ld a, h
+ or l
+ jr nz, 2$
+ djnz 1$
+ ret
diff --git a/asm/isr.asm b/asm/isr.asm
new file mode 100644
index 0000000..ad810e5
--- /dev/null
+++ b/asm/isr.asm
@@ -0,0 +1,17 @@
+ .module isr
+
+ .area _ISR_TABLE (REL)
+_ctc0_isr_ptr::
+ .dw #0
+_ctc1_isr_ptr::
+ .dw #_ctc1_isr
+_ctc2_isr_ptr::
+ .dw #_timer
+_ctc3_isr_ptr::
+ .dw #_blink_cursor
+_port_a_isr_ptr::
+ .dw #0
+_port_b_isr_ptr::
+ .dw #_input_event
+_rx_isr_ptr::
+ .dw #_rx_isr