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| author | Thomas Albers Raviola <thomas@thomaslabs.org> | 2024-12-03 21:45:47 +0100 |
|---|---|---|
| committer | Thomas Albers Raviola <thomas@thomaslabs.org> | 2024-12-03 21:45:47 +0100 |
| commit | d46862a5bd2319c595b11427f781201ca063d194 (patch) | |
| tree | e83d3f40c60233a1da85334745b882f188b0be52 /boot/crt0.asm | |
| parent | 9cd14efb76a4ddbcd013f44d50dc1ff93d56c4ca (diff) | |
Add bootloader
Diffstat (limited to 'boot/crt0.asm')
| -rw-r--r-- | boot/crt0.asm | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/boot/crt0.asm b/boot/crt0.asm new file mode 100644 index 0000000..09e4166 --- /dev/null +++ b/boot/crt0.asm @@ -0,0 +1,79 @@ +#include <hardware.h> + .module crt0 + .globl _main + + .area _HEADER (ABS) + .org 0x8000 +start: + di + ld a, #0x80 + ld i, a + ld sp, #0x0000 + jr main + .org 0x8010 +_ctc0_isr_ptr:: + .dw #0 +_ctc1_isr_ptr:: + .dw #_ctc1_isr +_ctc2_isr_ptr:: + .dw #0 +_ctc3_isr_ptr:: + .dw #0 +_port_a_isr_ptr:: + .dw #0 +_port_b_isr_ptr:: + .dw #0 +_rx_isr_ptr:: + .dw #_rx_isr +main: + 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 |