diff options
Diffstat (limited to 'c/src/lib/libcpu/m68k/m68040/fpsp/srem_mod.S')
| -rw-r--r-- | c/src/lib/libcpu/m68k/m68040/fpsp/srem_mod.S | 424 |
1 files changed, 0 insertions, 424 deletions
diff --git a/c/src/lib/libcpu/m68k/m68040/fpsp/srem_mod.S b/c/src/lib/libcpu/m68k/m68040/fpsp/srem_mod.S deleted file mode 100644 index 9453c9b7d0..0000000000 --- a/c/src/lib/libcpu/m68k/m68040/fpsp/srem_mod.S +++ /dev/null @@ -1,424 +0,0 @@ -#include "fpsp-namespace.h" -// -// -// srem_mod.sa 3.1 12/10/90 -// -// The entry point sMOD computes the floating point MOD of the -// input values X and Y. The entry point sREM computes the floating -// point (IEEE) REM of the input values X and Y. -// -// INPUT -// ----- -// Double-extended value Y is pointed to by address in register -// A0. Double-extended value X is located in -12(A0). The values -// of X and Y are both nonzero and finite; although either or both -// of them can be denormalized. The special cases of zeros, NaNs, -// and infinities are handled elsewhere. -// -// OUTPUT -// ------ -// FREM(X,Y) or FMOD(X,Y), depending on entry point. -// -// ALGORITHM -// --------- -// -// Step 1. Save and strip signs of X and Y: signX := sign(X), -// signY := sign(Y), X := |X|, Y := |Y|, -// signQ := signX EOR signY. Record whether MOD or REM -// is requested. -// -// Step 2. Set L := expo(X)-expo(Y), k := 0, Q := 0. -// If (L < 0) then -// R := X, go to Step 4. -// else -// R := 2^(-L)X, j := L. -// endif -// -// Step 3. Perform MOD(X,Y) -// 3.1 If R = Y, go to Step 9. -// 3.2 If R > Y, then { R := R - Y, Q := Q + 1} -// 3.3 If j = 0, go to Step 4. -// 3.4 k := k + 1, j := j - 1, Q := 2Q, R := 2R. Go to -// Step 3.1. -// -// Step 4. At this point, R = X - QY = MOD(X,Y). Set -// Last_Subtract := false (used in Step 7 below). If -// MOD is requested, go to Step 6. -// -// Step 5. R = MOD(X,Y), but REM(X,Y) is requested. -// 5.1 If R < Y/2, then R = MOD(X,Y) = REM(X,Y). Go to -// Step 6. -// 5.2 If R > Y/2, then { set Last_Subtract := true, -// Q := Q + 1, Y := signY*Y }. Go to Step 6. -// 5.3 This is the tricky case of R = Y/2. If Q is odd, -// then { Q := Q + 1, signX := -signX }. -// -// Step 6. R := signX*R. -// -// Step 7. If Last_Subtract = true, R := R - Y. -// -// Step 8. Return signQ, last 7 bits of Q, and R as required. -// -// Step 9. At this point, R = 2^(-j)*X - Q Y = Y. Thus, -// X = 2^(j)*(Q+1)Y. set Q := 2^(j)*(Q+1), -// R := 0. Return signQ, last 7 bits of Q, and R. -// -// - -// Copyright (C) Motorola, Inc. 1990 -// All Rights Reserved -// -// THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA -// The copyright notice above does not evidence any -// actual or intended publication of such source code. - -SREM_MOD: //idnt 2,1 | Motorola 040 Floating Point Software Package - - |section 8 - -#include "fpsp.defs" - - .set Mod_Flag,L_SCR3 - .set SignY,FP_SCR3+4 - .set SignX,FP_SCR3+8 - .set SignQ,FP_SCR3+12 - .set Sc_Flag,FP_SCR4 - - .set Y,FP_SCR1 - .set Y_Hi,Y+4 - .set Y_Lo,Y+8 - - .set R,FP_SCR2 - .set R_Hi,R+4 - .set R_Lo,R+8 - - -Scale: .long 0x00010000,0x80000000,0x00000000,0x00000000 - - |xref t_avoid_unsupp - - .global smod -smod: - - movel #0,Mod_Flag(%a6) - bras Mod_Rem - - .global srem -srem: - - movel #1,Mod_Flag(%a6) - -Mod_Rem: -//..Save sign of X and Y - moveml %d2-%d7,-(%a7) // ...save data registers - movew (%a0),%d3 - movew %d3,SignY(%a6) - andil #0x00007FFF,%d3 // ...Y := |Y| - -// - movel 4(%a0),%d4 - movel 8(%a0),%d5 // ...(D3,D4,D5) is |Y| - - tstl %d3 - bnes Y_Normal - - movel #0x00003FFE,%d3 // ...$3FFD + 1 - tstl %d4 - bnes HiY_not0 - -HiY_0: - movel %d5,%d4 - clrl %d5 - subil #32,%d3 - clrl %d6 - bfffo %d4{#0:#32},%d6 - lsll %d6,%d4 - subl %d6,%d3 // ...(D3,D4,D5) is normalized -// ...with bias $7FFD - bras Chk_X - -HiY_not0: - clrl %d6 - bfffo %d4{#0:#32},%d6 - subl %d6,%d3 - lsll %d6,%d4 - movel %d5,%d7 // ...a copy of D5 - lsll %d6,%d5 - negl %d6 - addil #32,%d6 - lsrl %d6,%d7 - orl %d7,%d4 // ...(D3,D4,D5) normalized -// ...with bias $7FFD - bras Chk_X - -Y_Normal: - addil #0x00003FFE,%d3 // ...(D3,D4,D5) normalized -// ...with bias $7FFD - -Chk_X: - movew -12(%a0),%d0 - movew %d0,SignX(%a6) - movew SignY(%a6),%d1 - eorl %d0,%d1 - andil #0x00008000,%d1 - movew %d1,SignQ(%a6) // ...sign(Q) obtained - andil #0x00007FFF,%d0 - movel -8(%a0),%d1 - movel -4(%a0),%d2 // ...(D0,D1,D2) is |X| - tstl %d0 - bnes X_Normal - movel #0x00003FFE,%d0 - tstl %d1 - bnes HiX_not0 - -HiX_0: - movel %d2,%d1 - clrl %d2 - subil #32,%d0 - clrl %d6 - bfffo %d1{#0:#32},%d6 - lsll %d6,%d1 - subl %d6,%d0 // ...(D0,D1,D2) is normalized -// ...with bias $7FFD - bras Init - -HiX_not0: - clrl %d6 - bfffo %d1{#0:#32},%d6 - subl %d6,%d0 - lsll %d6,%d1 - movel %d2,%d7 // ...a copy of D2 - lsll %d6,%d2 - negl %d6 - addil #32,%d6 - lsrl %d6,%d7 - orl %d7,%d1 // ...(D0,D1,D2) normalized -// ...with bias $7FFD - bras Init - -X_Normal: - addil #0x00003FFE,%d0 // ...(D0,D1,D2) normalized -// ...with bias $7FFD - -Init: -// - movel %d3,L_SCR1(%a6) // ...save biased expo(Y) - movel %d0,L_SCR2(%a6) //save d0 - subl %d3,%d0 // ...L := expo(X)-expo(Y) -// Move.L D0,L ...D0 is j - clrl %d6 // ...D6 := carry <- 0 - clrl %d3 // ...D3 is Q - moveal #0,%a1 // ...A1 is k; j+k=L, Q=0 - -//..(Carry,D1,D2) is R - tstl %d0 - bges Mod_Loop - -//..expo(X) < expo(Y). Thus X = mod(X,Y) -// - movel L_SCR2(%a6),%d0 //restore d0 - bra Get_Mod - -//..At this point R = 2^(-L)X; Q = 0; k = 0; and k+j = L - - -Mod_Loop: - tstl %d6 // ...test carry bit - bgts R_GT_Y - -//..At this point carry = 0, R = (D1,D2), Y = (D4,D5) - cmpl %d4,%d1 // ...compare hi(R) and hi(Y) - bnes R_NE_Y - cmpl %d5,%d2 // ...compare lo(R) and lo(Y) - bnes R_NE_Y - -//..At this point, R = Y - bra Rem_is_0 - -R_NE_Y: -//..use the borrow of the previous compare - bcss R_LT_Y // ...borrow is set iff R < Y - -R_GT_Y: -//..If Carry is set, then Y < (Carry,D1,D2) < 2Y. Otherwise, Carry = 0 -//..and Y < (D1,D2) < 2Y. Either way, perform R - Y - subl %d5,%d2 // ...lo(R) - lo(Y) - subxl %d4,%d1 // ...hi(R) - hi(Y) - clrl %d6 // ...clear carry - addql #1,%d3 // ...Q := Q + 1 - -R_LT_Y: -//..At this point, Carry=0, R < Y. R = 2^(k-L)X - QY; k+j = L; j >= 0. - tstl %d0 // ...see if j = 0. - beqs PostLoop - - addl %d3,%d3 // ...Q := 2Q - addl %d2,%d2 // ...lo(R) = 2lo(R) - roxll #1,%d1 // ...hi(R) = 2hi(R) + carry - scs %d6 // ...set Carry if 2(R) overflows - addql #1,%a1 // ...k := k+1 - subql #1,%d0 // ...j := j - 1 -//..At this point, R=(Carry,D1,D2) = 2^(k-L)X - QY, j+k=L, j >= 0, R < 2Y. - - bras Mod_Loop - -PostLoop: -//..k = L, j = 0, Carry = 0, R = (D1,D2) = X - QY, R < Y. - -//..normalize R. - movel L_SCR1(%a6),%d0 // ...new biased expo of R - tstl %d1 - bnes HiR_not0 - -HiR_0: - movel %d2,%d1 - clrl %d2 - subil #32,%d0 - clrl %d6 - bfffo %d1{#0:#32},%d6 - lsll %d6,%d1 - subl %d6,%d0 // ...(D0,D1,D2) is normalized -// ...with bias $7FFD - bras Get_Mod - -HiR_not0: - clrl %d6 - bfffo %d1{#0:#32},%d6 - bmis Get_Mod // ...already normalized - subl %d6,%d0 - lsll %d6,%d1 - movel %d2,%d7 // ...a copy of D2 - lsll %d6,%d2 - negl %d6 - addil #32,%d6 - lsrl %d6,%d7 - orl %d7,%d1 // ...(D0,D1,D2) normalized - -// -Get_Mod: - cmpil #0x000041FE,%d0 - bges No_Scale -Do_Scale: - movew %d0,R(%a6) - clrw R+2(%a6) - movel %d1,R_Hi(%a6) - movel %d2,R_Lo(%a6) - movel L_SCR1(%a6),%d6 - movew %d6,Y(%a6) - clrw Y+2(%a6) - movel %d4,Y_Hi(%a6) - movel %d5,Y_Lo(%a6) - fmovex R(%a6),%fp0 // ...no exception - movel #1,Sc_Flag(%a6) - bras ModOrRem -No_Scale: - movel %d1,R_Hi(%a6) - movel %d2,R_Lo(%a6) - subil #0x3FFE,%d0 - movew %d0,R(%a6) - clrw R+2(%a6) - movel L_SCR1(%a6),%d6 - subil #0x3FFE,%d6 - movel %d6,L_SCR1(%a6) - fmovex R(%a6),%fp0 - movew %d6,Y(%a6) - movel %d4,Y_Hi(%a6) - movel %d5,Y_Lo(%a6) - movel #0,Sc_Flag(%a6) - -// - - -ModOrRem: - movel Mod_Flag(%a6),%d6 - beqs Fix_Sign - - movel L_SCR1(%a6),%d6 // ...new biased expo(Y) - subql #1,%d6 // ...biased expo(Y/2) - cmpl %d6,%d0 - blts Fix_Sign - bgts Last_Sub - - cmpl %d4,%d1 - bnes Not_EQ - cmpl %d5,%d2 - bnes Not_EQ - bra Tie_Case - -Not_EQ: - bcss Fix_Sign - -Last_Sub: -// - fsubx Y(%a6),%fp0 // ...no exceptions - addql #1,%d3 // ...Q := Q + 1 - -// - -Fix_Sign: -//..Get sign of X - movew SignX(%a6),%d6 - bges Get_Q - fnegx %fp0 - -//..Get Q -// -Get_Q: - clrl %d6 - movew SignQ(%a6),%d6 // ...D6 is sign(Q) - movel #8,%d7 - lsrl %d7,%d6 - andil #0x0000007F,%d3 // ...7 bits of Q - orl %d6,%d3 // ...sign and bits of Q - swap %d3 - fmovel %fpsr,%d6 - andil #0xFF00FFFF,%d6 - orl %d3,%d6 - fmovel %d6,%fpsr // ...put Q in fpsr - -// -Restore: - moveml (%a7)+,%d2-%d7 - fmovel USER_FPCR(%a6),%fpcr - movel Sc_Flag(%a6),%d0 - beqs Finish - fmulx Scale(%pc),%fp0 // ...may cause underflow - bra t_avoid_unsupp //check for denorm as a -// ;result of the scaling - -Finish: - fmovex %fp0,%fp0 //capture exceptions & round - rts - -Rem_is_0: -//..R = 2^(-j)X - Q Y = Y, thus R = 0 and quotient = 2^j (Q+1) - addql #1,%d3 - cmpil #8,%d0 // ...D0 is j - bges Q_Big - - lsll %d0,%d3 - bras Set_R_0 - -Q_Big: - clrl %d3 - -Set_R_0: - fmoves #0x00000000,%fp0 - movel #0,Sc_Flag(%a6) - bra Fix_Sign - -Tie_Case: -//..Check parity of Q - movel %d3,%d6 - andil #0x00000001,%d6 - tstl %d6 - beq Fix_Sign // ...Q is even - -//..Q is odd, Q := Q + 1, signX := -signX - addql #1,%d3 - movew SignX(%a6),%d6 - eoril #0x00008000,%d6 - movew %d6,SignX(%a6) - bra Fix_Sign - - //end |