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v2.1R6 - Fix Pack 6

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@humbertocsjr humbertocsjr released this 06 May 07:05
· 3 commits to main since this release
v2.1R6
e4a45f6

v2.1 R6 - May 2026

B Compiler (hcbcomp)

Z80 Peephole Optimizations - Bug Fixes

  • Pattern 15 (z80_match_inc_local_full): fixed to match complete 21-instruction sequence (was 19)
    • Added missing final instructions: pop de and ex de, hl from gen_pop_sec() and gen_exchange()
    • Eliminates leftover pop de; ex de, hl after optimized inc word [ix+N]
  • Pattern 16 (z80_match_dec_local_full): fixed to match complete 23-instruction sequence (was 21)
    • Added missing final instructions: pop de and ex de, hl from gen_pop_sec() and gen_exchange()
    • Eliminates leftover pop de; ex de, hl after optimized dec word [ix+N]
  • Dispatcher updated: wcount checks changed from 19/21 to 21/23 in gen_peep_replace()

Example - Before Fix

inc word [ix-2]
pop de          ; ← leftover (useless)
ex de, hl       ; ← leftover (useless)
push ix         ; ← next code

Example - After Fix

inc word [ix-2]
push ix         ; ← next code (no leftovers)

Assembler (hcasm)

Z80 IM Instruction Fix

  • Bug fix in emit_im(): corrected token validation condition
    • Changed argv[0]->token != TOK_VALUE to argv[0]->token == TOK_VALUE
    • Instructions IM 0, IM 1, IM 2 now assemble correctly
  • Test impact: asm/z80/all_opcodes now passes (was failing due to IM instruction error)

Validation & Testing

  • 43/43 tests passing (was 42/43)
  • Zero regressions - all B language and assembler tests pass across all platforms

v2.1 R5 - May 2026

B Compiler (hcbcomp)

Z80 Peephole Optimizations - Local Variable Increment/Decrement

  • Pattern 15 (z80_match_inc_local_full): replaces 19-instruction increment sequence with inc word [ix+N]
    • Pattern: push ix; pop hl; ld de,OFF; add hl,de; push hl; ld a,[hl]; inc hl; ld h,[hl]; ld l,a; push hl; push hl; ld hl,1; pop de; add hl,de; pop de; ex de,hl; ld [hl],e; inc hl; ld [hl],d
    • Replacement: inc word [ix+OFF]
    • Optimization: 19 → 1 instructions (95% reduction)
  • Pattern 16 (z80_match_dec_local_full): replaces 21-instruction decrement sequence with dec word [ix+N]
    • Pattern: push ix; pop hl; ld de,OFF; add hl,de; push hl; ld a,[hl]; inc hl; ld h,[hl]; ld l,a; push hl; push hl; ld hl,1; pop de; ex de,hl; or a; sbc hl,de; pop de; ex de,hl; ld [hl],e; inc hl; ld [hl],d
    • Replacement: dec word [ix+OFF]
    • Optimization: 21 → 1 instructions (95% reduction)
  • Window size increased: PEEP_WINDOW from 12 to 25 to support larger pattern matching

Example Optimization

; Before (a++)
push ix
pop hl
ld de, -2
add hl, de
push hl
ld a, [hl]
inc hl
ld h, [hl]
ld l, a
push hl
push hl
ld hl, 1
pop de
add hl, de
pop de
ex de, hl
ld [hl], e
inc hl
ld [hl], d

; After
inc word [ix-2]

Validation & Testing

  • 42/42 tests passing across all platforms (Z80, 8080, 8085, 8086, 8086exe)
  • Zero regressions - all official B language tests continue passing

Performance Impact

Platform Optimization Before After Savings
Z80 inc word [ix+N] 19 instr 1 instr 95% fewer instructions
Z80 dec word [ix+N] 21 instr 1 instr 95% fewer instructions

Overall impact: Significant code size reduction and speedup for programs using ++ and -- operators on local variables

Assets 12
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