Hi, Please find below a patch that optimizes libgcc routines for the RL78 target.
This is similar to my earlier patch submitted here, https://gcc.gnu.org/ml/gcc-patches/2016-02/msg00415.html The patch optimizes the loading of immediate value in the case of 0x00, by using the clrw or clrb instruction. The patch replaces movw/mov instruction with the smaller clrw/clrb instruction. The clrw and clrb generates only 1 byte of opcode as compared to 3 or 2 bytes for movw and mov. Kindly review this patch and let me know what you think. This is regression tested for rl78 -msim. Best Regards, Kaushik p.s. Kindly ignore any disclaimers at end of this e-mail as they are auto-inserted. Apologies for the same. 2016-04-06 Kaushik Phatak <kaushik.pha...@kpit.com> * config/rl78/bit-count.S: Use clrw/clrb where possible. * config/rl78/cmpsi2.S: Likewise. * config/rl78/divmodhi.S Likewise. * config/rl78/divmodsi.S Likewise. * config/rl78/fpbit-sf.S Likewise. * config/rl78/fpmath-sf.S Likewise. * config/rl78/mulsi3.S Likewise. Index: libgcc/config/rl78/bit-count.S =================================================================== --- libgcc/config/rl78/bit-count.S (revision 3174) +++ libgcc/config/rl78/bit-count.S (working copy) @@ -139,7 +139,7 @@ xor1 cy, a.5 xor1 cy, a.6 xor1 cy, a.7 - movw ax, #0 + clrw ax bnc $1f incw ax 1: @@ -190,7 +190,7 @@ movw ax, sp addw ax, #4 movw hl, ax - mov a, #0 + clrb a 1: xch a, b mov a, [hl] @@ -207,7 +207,7 @@ bnz $1b mov x, a - mov a, #0 + clrb a movw r8, ax ret END_FUNC ___popcountqi_internal Index: libgcc/config/rl78/cmpsi2.S =================================================================== --- libgcc/config/rl78/cmpsi2.S (revision 3174) +++ libgcc/config/rl78/cmpsi2.S (working copy) @@ -162,8 +162,8 @@ ;; They differ. Subtract *S2 from *S1 and return as the result. mov x, a - mov a, #0 - mov r9, #0 + clrb a + clrb r9 subw ax, r8 1: movw r8, ax Index: libgcc/config/rl78/divmodhi.S =================================================================== --- libgcc/config/rl78/divmodhi.S (revision 3174) +++ libgcc/config/rl78/divmodhi.S (working copy) @@ -576,7 +576,7 @@ .macro NEG_AX movw hl, ax - movw ax, #0 + clrw ax subw ax, [hl] movw [hl], ax .endm Index: libgcc/config/rl78/divmodsi.S =================================================================== --- libgcc/config/rl78/divmodsi.S (revision 3174) +++ libgcc/config/rl78/divmodsi.S (working copy) @@ -952,10 +952,10 @@ .macro NEG_AX movw hl, ax - movw ax, #0 + clrw ax subw ax, [hl] movw [hl], ax - movw ax, #0 + clrw ax sknc decw ax subw ax, [hl+2] Index: libgcc/config/rl78/fpbit-sf.S =================================================================== --- libgcc/config/rl78/fpbit-sf.S (revision 3174) +++ libgcc/config/rl78/fpbit-sf.S (working copy) @@ -117,7 +117,7 @@ call $!__int_iszero bnz $2f ;; At this point, both args are zero. - mov a, #0 + clrb a ret 2: @@ -151,7 +151,7 @@ bc $ybig_cmpsf ; branch if X < Y bnz $xbig_cmpsf ; branch if X > Y - mov a, #0 + clrb a ret xbig_cmpsf: ; |X| > |Y| so return A = 1 if pos, 0xff if neg @@ -285,7 +285,7 @@ movw r10, #0x7fff ret ;; -inf -2: mov r8, #0 +2: clrb r8 mov r10, #0x8000 ret @@ -302,10 +302,10 @@ clr1 a.7 call $!__int_fixunssfsi - movw ax, #0 + clrw ax subw ax, r8 movw r8, ax - movw ax, #0 + clrw ax sknc decw ax subw ax, r10 @@ -410,7 +410,7 @@ set1 a.7 ;; Clear B:C:R12:R13 - movw bc, #0 + clrw bc movw r12, #0 ;; Shift bits from the mantissa (A:X:R10) into (B:C:R12:R13), @@ -482,10 +482,10 @@ ;; If negative convert to positive ... movw hl, ax - movw ax, #0 + clrw ax subw ax, bc movw bc, ax - movw ax, #0 + clrw ax sknc decw ax subw ax, hl @@ -533,7 +533,7 @@ bnz $1f movw ax, bc cmpw ax, #0 - movw ax, #0 + clrw ax bnz $1f ;; Return 0.0 Index: libgcc/config/rl78/fpmath-sf.S =================================================================== --- libgcc/config/rl78/fpmath-sf.S (revision 3174) +++ libgcc/config/rl78/fpmath-sf.S (working copy) @@ -87,7 +87,7 @@ or a, #0x80 mov A_FRAC_H, a - mov a, #0 + clrb a mov A_FRAC_HH, a ;; rounding-bit-shift @@ -273,7 +273,7 @@ ;; "zero out" b movw ax, A_EXP movw B_EXP, ax - movw ax, #0 + clrw ax movw B_FRAC_L, ax movw B_FRAC_H, ax br $5f @@ -281,7 +281,7 @@ ;; "zero out" a movw ax, B_EXP movw A_EXP, ax - movw ax, #0 + clrw ax movw A_FRAC_L, ax movw A_FRAC_H, ax @@ -379,7 +379,7 @@ bt a.7, $.L706 ;; subtraction was positive - mov a, #0 + clrb a mov A_SIGN, a br $.L712 @@ -543,7 +543,7 @@ or a, A_FRAC_H or a, A_FRAC_HH bnz $1f - movw ax, #0 + clrw ax movw A_EXP, ax 1: mov a, A_FRAC_H @@ -682,7 +682,7 @@ movw ax, B_FRAC_H movw [sp+10], ax - movw ax, #0 + clrw ax movw [sp+4], ax movw [sp+6], ax movw [sp+12], ax @@ -867,7 +867,7 @@ and a, #0x80 mov r11, a movw r8, #0 - mov r10, #0 + clrb r10 ret 1: @@ -930,7 +930,7 @@ movw ax, B_FRAC_H movw [sp+10], ax - movw ax, #0 + clrw ax movw [sp+0], ax movw [sp+2], ax movw [sp+12], ax Index: libgcc/config/rl78/mulsi3.S =================================================================== --- libgcc/config/rl78/mulsi3.S (revision 3174) +++ libgcc/config/rl78/mulsi3.S (working copy) @@ -148,7 +148,7 @@ movw ax, bc .Lmul_hisi_top: - movw bc, #0 + clrw bc .Lmul_hisi_loop: shrw ax, 1
rl78_libgcc_optimize_clrw.patch
Description: rl78_libgcc_optimize_clrw.patch
