First commit

1 files changed, 50 insertions, 0 deletions

diff --git a/libpsn00b/psxgpu/setvideomode.s b/libpsn00b/psxgpu/setvideomode.s
new file mode 100644
index 0000000..718a4dd
--- /dev/null
+++ b/libpsn00b/psxgpu/setvideomode.s
@@ -0,0 +1,50 @@
+.set noreorder
+
+.include "hwregs_a.h"
+
+
+.section .text
+
+.global SetVideoMode
+.type SetVideoMode, @function
+SetVideoMode:
+	addiu	$sp, -4
+	sw		$ra, 0($sp)
+
+	jal		ReadGPUstat
+	nop
+
+	srl		$a1, $v0, 17
+	andi	$a1, 0x1f
+
+	srl		$v1, $v0, 14			# Reverse flag
+	andi	$v1, 1
+	sll		$v1, 6
+	or		$a1, $v1
+
+	srl		$v1, $v0, 16			# Horizontal resolution 2
+	andi	$v1, 1
+	sll		$v1, 6
+	or		$a1, $v1
+
+	andi	$a1, 0xf7				# Mask off PAL bit
+
+	la		$v0, _gpu_standard
+	beqz	$a0, .set_done
+	sw		$0 , 0($v0)
+	li		$v1, 1
+	sw		$v1, 0($v0)
+	b		.set_done
+	or		$a1, 0x8
+.set_done:
+
+	lui		$v0, 0x800				# Apply new mode
+	or		$a1, $v0
+	lui		$v0, IOBASE
+	sw		$a1, GP1($v0)
+
+	lw		$ra, 0($sp)
+	addiu	$sp, 4
+	jr		$ra
+	nop
+