# r0 volatile, may be used by function linkage # r1 stack pointer # r2 table of contents register # r3 .. r4 volatile, pass 1st - 2nd int args, return 1st - 2nd ints # r5 .. r10 volatile, pass 3rd - 8th int args # r11 volatile, pass static chain if language needs it # r12 volatile, used by dyn linker, exception handling # r13 .. r31 saved # f0 volatile # f1 .. f4 volatile, pass 1st - 4th float args, return 1st - 4th floats # f5 .. f13 volatile, pass 5th - 13th float args # f14 .. f31 saved # Use r23 as CurCnt # Use r24 as MaxCnt (Constant value) # Use r25 as LPixelBuf # Use r26 as location within ColorTable32 # Use r27 as base address of ColorTable32 # Use r28 as BPP (that is, bytes per pixel) # r29 as RightEdge # r30 as xtemp (integer) # Note that the following are constants, and independent of xtemp. # First the integers # MaxCnt in r24 # LPixelBuf in r25. It changes but need only be loaded 1 time. # Base address of ColorTable32 in r27 # BPP in r28 # Now the floats (Newly defined) # xRel in f15 (changes as DX is added in on each pass) # Use f16 as value of yRel. This is constant for each line. # Use f17 as value that was stored in 40(r1). It's Zi # Use f18 as Zr. # Use f19 as |Zr2| + |Zi2| Only for comparing with Limit. # Use f20 This is scratch and used shortly for 2Zi. # Delta x in f21 # Two in f22 # Limit in f23 # Use f24 as Zr2. This is also a temporary value #vsc elf .text .sdreg 13 .global UseLibP2 .align 4 UseLibP2: mflr 11 stw 11,4(1) #Save return address stwu 1,-80(1) #Save stack pointer fmr 16,1 #Transfer yrel from f1 to f16 lis 11,MaxCnt@ha lwz 24,MaxCnt@l(11) #MaxCnt in r24. lis 11,LPixelBuf@ha lwz 25,LPixelBuf@l(11) #Get Location of LPixelBuf lis 11,ColorTable32@ha lwz 27,ColorTable32@l(11) #Start of color table lis 11,BPP@ha lwz 28,BPP@l(11) #Number bytes per pixel lis 11,Factor@ha lfd 25,Factor@l(11) #Get Factor into f25 lis 11,Two@ha lfd 22,Two@l(11) #Get Two into f22 as constant lis 11,Limit@ha lfd 23,Limit@l(11) #Get Limit into f23 as constant li 30,0 #xtemp = 0. # Convert xtemp to double fp. lis 12,17200 #r12 = 0x4330 lis 11,.l14@ha stw 12,.l14@l(11) #Place in buffer xoris 12,30,32768 #XOR with 0x8000 lis 18,.l15@ha stw 12,.l15@l(18) #Store in high word of buffer lis 11,.l14@ha lfd 0,.l14@l(11) #Get back as double lis 11,.l13@ha lfd 10,.l13@l(11) fsub 15,0,10 #Find (double)xtemp lis 11,XCenter@ha lfd 10,XCenter@l(11) #f10 = XCenter fsub 15,15,10 #xRel = xRel - XCenter fdiv 15,15,25 #xRel = xRel/Factor lis 11,DX@ha lfd 21,DX@l(11) #Get the real value of Delta x. lis 11,RightEdge@ha lwz 29,RightEdge@l(11) Start: fmr 18,15 #Initial value of Zr is xRel. # The following line was moved before rather than after fmr f17,f16 # to give the fpu a break. li 23,1 #Initialize CurCnt = 1 fmr 17,16 #yRel into f17 as initial Zi. b l3 #Check to see if to MaxCnt l2: fmul 24,18,18 #Zr2 in f24 fmul 4,17,17 #Zi2 = Zi*Zi fadd 19,24,4 fcmpu 0,19,23 #Compare with Limit in f23. ble 0,l6 #The following section is not very time-critical as it is only reached once. #for each pixel cmpwi 0,28,2 #See if BPP < 2 blt 0,l8 l7: slwi 10,23,2 #4 times CurCnt for offset in ColorTable32 add 26,27,10 #Find location of pixel color in ColorTable32 lwz 11,0(26) #Get ARGB from ColorTable stw 11,0(25) #Store color in LPixelBuf addi 25,25,4 #Point to next location in LPixelBuf b l1 l8: andi. 3,23,65535 #Prep for storage as UWORD bl PlotIt l9: b l1 l6: fmul 20,22,17 #Find 2*Zi (Two in f22) fsub 10,24,4 #Zr2 = Zr2 - Zi2 fmul 17,20,18 #Find 2*Zi*Zr (temporary Zi) addi 23,23,1 #Increment CurCnt fadd 18,15,10 #New Zr = xRel + Zr2 fadd 17,16,17 #Zi = Zi + yRel l3: cmpw 0,23,24 #See if CurCnt < MaxCnt blt 0,l2 #Repeat until MaxCnt reached cmpwi 0,28,2 #See if BPP < 2 blt 0,l11 l10: lis 12,4 addi 12,12,-4 add 26,27,12 #Find location of pixel color lwz 11,0(26) #Get color stw 11,0(25) #Store color in LPixelBuf addi 25,25,4 #Point to next pixel in buffer b l1 #Was l12 l11: lis 11,1 addi 3,11,-1 #ffff into r3 for PlotIt bl PlotIt l1: fadd 15,15,21 #Find new value of xRel. addi 30,30,1 #Increment xtemp. cmpw 0,30,29 #See if to RightEdge blt 0,Start #Repeat until row is done. lis 11,LPixelBuf@ha stw 25,LPixelBuf@l(11) #New location in long pixel buffer addi 1,1,80 #Balance Stack pointer lwz 11,4(1) #Get return address mtlr 11 blr .type UseLibP2,@function .size UseLibP2,$-UseLibP2 .globl MaxCnt .globl RightEdge .globl XCenter .globl Factor .globl Limit .globl Two .globl LPixelBuf .globl ColorTable32 .globl BPP .globl DX .globl PlotIt .section .rodata .align 2 .align 3 .l13: .long 0x43300000,0x80000000 .l14: .word 0 .l15: .word 0,0,0