Swap Framebuffer Video Output Screen

00042d18: 27bdffd8 addiu r29,r29,0xffd8
00042d1c: afb1001c sw r17,0x001c(r29)
00042d20: 00808821 addu r17,r4,r0                OTAG list to draw
00042d24: 3c028004 lui r2,0x8004
00042d28: 8c42597c lw r2,0x597c(r2)
00042d2c: afbf0020 sw r31,0x0020(r29)
00042d30: afb00018 sw r16,0x0018(r29)
00042d34: 2c420001 sltiu r2,r2,0x0001
00042d38: 3c018004 lui r1,0x8004
00042d3c: ac22597c sw r2,0x597c(r1)              swap screen polarity
00042d40: 0c0091b5 jal 0x000246d4                SYS DrawSync
00042d44: 00002021 addu r4,r0,r0
00042d48: 0c0076ea jal 0x0001dba8                VSync call
00042d4c: 00002021 addu r4,r0,r0
00042d50: 3c038004 lui r3,0x8004
00042d54: 8c63597c lw r3,0x597c(r3)              current screen polarity
00042d58: 00408021 addu r16,r2,r0                return time since boot
00042d5c: 00032080 sll r4,r3,0x02
00042d60: 00832021 addu r4,r4,r3
00042d64: 00042080 sll r4,r4,0x02
00042d68: 3c038005 lui r3,0x8005
00042d6c: 2463eacc addiu r3,r3,0xeacc            
00042d70: 0c0093a1 jal 0x00024e84                SYS PutDispEnv
00042d74: 00832021 addu r4,r4,r3                 current screen disp environment
00042d78: 3c028004 lui r2,0x8004
00042d7c: 8c42597c lw r2,0x597c(r2)
00042d80: 00000000 nop
00042d84: 00022040 sll r4,r2,0x01
00042d88: 00822021 addu r4,r4,r2
00042d8c: 000420c0 sll r4,r4,0x03
00042d90: 00822023 subu r4,r4,r2
00042d94: 00042080 sll r4,r4,0x02
00042d98: 3c028005 lui r2,0x8005
00042d9c: 2442ea14 addiu r2,r2,0xea14
00042da0: 0c00932b jal 0x00024cac                SYS PutDrawEnv
00042da4: 00822021 addu r4,r4,r2                 current screen draw environment
00042da8: 0c00930e jal 0x00024c38                SYS DrawOtag
00042dac: 02202021 addu r4,r17,r0
00042db0: 0c008ca2 jal 0x00023288                FONT FntFlush
00042db4: 2404ffff addiu r4,r0,0xffff            -1
00042db8: 02001021 addu r2,r16,r0                return time since boot
00042dbc: 8fbf0020 lw r31,0x0020(r29)
00042dc0: 8fb1001c lw r17,0x001c(r29)
00042dc4: 8fb00018 lw r16,0x0018(r29)
00042dc8: 27bd0028 addiu r29,r29,0x0028
00042dcc: 03e00008 jr r31
00042dd0: 00000000 nop