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- Q = 0
- N = 1
- D = 2
- CC = 3
- TMP = 11
- TEXT save<>(SB), 1, $0
- MOVW R(Q), 0(FP)
- MOVW R(N), 4(FP)
- MOVW R(D), 8(FP)
- MOVW R(CC), 12(FP)
- MOVW R(TMP), R(Q) /* numerator */
- MOVW 20(FP), R(D) /* denominator */
- CMP $0, R(D)
- BNE s1
- SWI 0
- /* MOVW -1(R(D)), R(TMP) /* divide by zero fault */
- s1: RET
- TEXT rest<>(SB), 1, $0
- MOVW 0(FP), R(Q)
- MOVW 4(FP), R(N)
- MOVW 8(FP), R(D)
- MOVW 12(FP), R(CC)
- /*
- * return to caller
- * of rest<>
- */
- MOVW 0(R13), R14
- ADD $20, R13
- B (R14)
- TEXT div<>(SB), 1, $0
- MOVW $32, R(CC)
- /*
- * skip zeros 8-at-a-time
- */
- e1:
- AND.S $(0xff<<24),R(Q), R(N)
- BNE e2
- SLL $8, R(Q)
- SUB.S $8, R(CC)
- BNE e1
- RET
- e2:
- MOVW $0, R(N)
- loop:
- /*
- * shift R(N||Q) left one
- */
- SLL $1, R(N)
- CMP $0, R(Q)
- ORR.LT $1, R(N)
- SLL $1, R(Q)
- /*
- * compare numerator to denominator
- * if less, subtract and set quotent bit
- */
- CMP R(D), R(N)
- ORR.HS $1, R(Q)
- SUB.HS R(D), R(N)
- SUB.S $1, R(CC)
- BNE loop
- RET
- TEXT _div(SB), 1, $16
- BL save<>(SB)
- CMP $0, R(Q)
- BGE d1
- RSB $0, R(Q), R(Q)
- CMP $0, R(D)
- BGE d2
- RSB $0, R(D), R(D)
- d0:
- BL div<>(SB) /* none/both neg */
- MOVW R(Q), R(TMP)
- B out
- d1:
- CMP $0, R(D)
- BGE d0
- RSB $0, R(D), R(D)
- d2:
- BL div<>(SB) /* one neg */
- RSB $0, R(Q), R(TMP)
- B out
- TEXT _mod(SB), 1, $16
- BL save<>(SB)
- CMP $0, R(D)
- RSB.LT $0, R(D), R(D)
- CMP $0, R(Q)
- BGE m1
- RSB $0, R(Q), R(Q)
- BL div<>(SB) /* neg numerator */
- RSB $0, R(N), R(TMP)
- B out
- m1:
- BL div<>(SB) /* pos numerator */
- MOVW R(N), R(TMP)
- B out
- TEXT _divu(SB), 1, $16
- BL save<>(SB)
- BL div<>(SB)
- MOVW R(Q), R(TMP)
- B out
- TEXT _modu(SB), 1, $16
- BL save<>(SB)
- BL div<>(SB)
- MOVW R(N), R(TMP)
- B out
- out:
- BL rest<>(SB)
- B out
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