scc

Simple C99 Compiler
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commit f957dc886547ffab16c9f743889f51f23726f13a
parent 6a7fb9b9a0a08b584646222fdc7cd1ec03a7230c
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Thu, 19 Mar 2015 20:45:17 +0000

Add spill()

This function spill variable associated to a register into memory.

Diffstat:
cc2/cc2.h | 2++
cc2/cgen.c | 86++++++++++++++++++++++++++++++++++++++++++++++++++-----------------------------
cc2/parser.c | 5++++-
3 files changed, 61 insertions(+), 32 deletions(-)

diff --git a/cc2/cc2.h b/cc2/cc2.h @@ -53,8 +53,10 @@ typedef struct { struct symbol { unsigned short id; char *name; + char kind; bool public : 1; bool extrn : 1; + bool dirty : 1; union { /* TODO: Admit inmediate of other type */ TINT imm; diff --git a/cc2/cgen.c b/cc2/cgen.c @@ -12,10 +12,10 @@ static uint8_t upper[] = {[DE] = D, [HL] = H, [BC] = B, [IY] = IYH}; static uint8_t lower[] = {[DE] = E, [HL] = L, [BC] = C, [IY] = IYL}; static uint8_t pair[] = { [A] = A, - [H] = HL, [L] = HL, - [B] = BC, [C] = BC, - [D] = DE, [E] = DE, - [IYL] = IY, [IYH] = IY + [H] = HL, [L] = HL, [HL] = HL, + [B] = BC, [C] = BC, [BC] = BC, + [D] = DE, [E] = DE, [DE] = DE, + [IYL] = IY, [IYH] = IY, [IY] = IY }; Node @@ -117,6 +117,41 @@ allocreg(Node *np) } static void +spill(uint8_t reg) +{ + Node *np, *r; + Symbol *sym; + uint8_t p, h, l; + + if ((np = reguse[reg]) == NULL) + return; + if ((sym = np->sym) == NULL) + goto freereg; + if (!sym->dirty) + goto freereg; + + r = regs[reg]; + switch (np->type.size) { + case 1: + code(LDL, np, r); + break; + default: + abort(); + } + sym->dirty = 0; + +freereg: + reguse[reg] = NULL; + p = pair[reg]; + l = lower[p]; + h = upper[p]; + if (reg >= NREGS) + reguse[l] = reguse[h] = NULL; + else if (!reguse[l] && !reguse[h]) + reguse[p] = NULL; +} + +static void moveto(Node *np, uint8_t reg) { Node *r = regs[reg], *u = reguse[reg]; @@ -127,7 +162,7 @@ moveto(Node *np, uint8_t reg) if (op == u->op && sym && sym == u->sym) return; else - ; /* TODO: Push the value? */ + spill(reg); } switch (np->type.size) { @@ -164,7 +199,7 @@ moveto(Node *np, uint8_t reg) default: abort(); } - reguse[reg] = np; + reguse[pair[reg]] = reguse[reg] = np; np->op = REG; np->reg = reg; } @@ -176,31 +211,17 @@ move(Node *np) } static void -push(uint8_t reg) -{ - Node *np; - - if (reg < NREGS) - reg = pair[reg]; - if ((np = reguse[lower[reg]]) != NULL) - np->op = PUSHED; - if ((np = reguse[upper[reg]]) != NULL) - np->op = PUSHED; - code(PUSH, NULL, regs[reg]); -} - -static void accum(Node *np) { + Symbol *sym; + switch (np->type.size) { case 1: - if (reguse[A]) - push(A); + spill(A); moveto(np, A); break; case 2: - if (reguse[H] || reguse[L]) - push(HL); + spill(HL); moveto(np, HL); break; case 4: @@ -214,14 +235,13 @@ index(Node *np) { Node *u = reguse[HL]; - if (u) { - Symbol *sym = np->sym; - - if (u->op == INDEX && sym && sym == u->sym) { + if (u && u->sym) { + if (u->op == INDEX && np->sym == u->sym) { np->op = INDEX; return; - } else - ; /* TODO: Push the value? */ + } else { + spill(HL); + } } code(LDI, &reg_HL, np); np->op = INDEX; @@ -295,7 +315,7 @@ add(Node *np) break; default: abort(); - } + } break; default: abort(); @@ -316,6 +336,7 @@ static void assign(Node *np) { Node *lp = np->left, *rp = np->right; + Symbol *sym = lp->sym; assert(rp->op == REG); switch (np->type.size) { @@ -340,6 +361,9 @@ assign(Node *np) default: abort(); } + + if (sym) + sym->dirty = 0; np->op = REG; np->reg = rp->reg; } diff --git a/cc2/parser.c b/cc2/parser.c @@ -287,12 +287,15 @@ gettype(char *type) static Symbol * symbol(uint8_t t, char *token) { + Symbol *sym; static Symbol *(*tbl[3])(char *)= { [LOCAL] = local, [GLOBAL] = global, [PARAMETER] = parameter }; - return (*tbl[t])(token+1); + sym = (*tbl[t])(token+1); + sym->kind = *token; + return sym; } static void