diff options
| author | Thomas Albers Raviola <thomas@thomaslabs.org> | 2025-02-12 01:27:44 +0100 |
|---|---|---|
| committer | Thomas Albers Raviola <thomas@thomaslabs.org> | 2025-02-12 01:27:44 +0100 |
| commit | 779b9834e30de1ba0b4f0755388bebd0c45aa1dc (patch) | |
| tree | 218edb656e329884e4b9cab7e84f4ba4b4af0c4a /asm | |
| parent | 8ac78b9953908d2a4ffece855296fb7597440cce (diff) | |
Restructure rom image and use dependencies for makefiles
Diffstat (limited to 'asm')
| -rw-r--r-- | asm/crt0.asm | 75 |
1 files changed, 30 insertions, 45 deletions
diff --git a/asm/crt0.asm b/asm/crt0.asm index fd03997..a53c9e8 100644 --- a/asm/crt0.asm +++ b/asm/crt0.asm @@ -1,32 +1,17 @@ #include <hardware.h> - .module crt0 - .globl _main + .module crt0 + .globl _main .area _HEADER (ABS) - .org 0x0000 + .org 0x8000 start: - di - xor a - ld i, a - ld sp, #0x0000 - ;; Init PIO and check for KEY2 - ld a, #PIO_MODE_3 - out (PORT_B_CTRL), a - ld a, #0x7F - out (PORT_B_CTRL), a - in a, (PORT_B_DATA) - and #KEY2 ; is KEY2 pressed? If so, start booloader - jr NZ, main - ;; Load payload (bootloader) - ld hl, #0x7000 ; src - ld de, #0x8000 ; dest - ld bc, #0x1000 ; size - ldir - ;; Start bootloader - jp 0x8000 + di + ld a, #0x80 + ld i, a + ld sp, #0x0000 main: - call gsinit + call gsinit call _main 1$: halt @@ -36,44 +21,44 @@ main: .area _HOME .area _CODE .area _INITIALIZER - .area _GSINIT - .area _GSFINAL + .area _GSINIT + .area _GSFINAL .area _DATA .area _INITIALIZED .area _BSEG - .area _BSS - .area _HEAP + .area _BSS + .area _HEAP - .area _CODE + .area _CODE - .area _GSINIT + .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 + 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 + jr z, gsinit_next ld de, #s__INITIALIZED ld hl, #s__INITIALIZER ldir gsinit_next: - .area _GSFINAL + .area _GSFINAL ret |