80 lines
2.1 KiB
C++
80 lines
2.1 KiB
C++
namespace factor {
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inline static void* frame_return_address(void* frame_top) {
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return *(void**)frame_top;
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}
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inline static void set_frame_return_address(void* frame_top,
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void* return_address) {
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*(void**)frame_top = return_address;
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}
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#define CALLSTACK_BOTTOM(ctx) \
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(void*)(ctx->callstack_seg->end - sizeof(cell) * 5)
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inline static void flush_icache(cell start, cell len) {}
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/* In the instruction sequence:
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MOV EBX,...
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JMP blah
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the offset from the immediate operand to MOV to the instruction after
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the jump is a cell for the immediate operand, 4 bytes for the JMP
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destination, and one byte for the JMP opcode. */
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static const fixnum xt_tail_pic_offset = 4 + 1;
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static const unsigned char call_opcode = 0xe8;
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static const unsigned char jmp_opcode = 0xe9;
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inline static unsigned char call_site_opcode(cell return_address) {
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return *(unsigned char*)(return_address - 5);
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}
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inline static void check_call_site(cell return_address) {
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unsigned char opcode = call_site_opcode(return_address);
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FACTOR_ASSERT(opcode == call_opcode || opcode == jmp_opcode);
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(void)opcode; // suppress warning when compiling without assertions
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}
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inline static void* get_call_target(cell return_address) {
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check_call_site(return_address);
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return (void*)(*(int*)(return_address - 4) + return_address);
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}
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inline static void set_call_target(cell return_address, void* target) {
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check_call_site(return_address);
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*(int*)(return_address - 4) = (uint32_t)((cell)target - return_address);
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}
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inline static bool tail_call_site_p(cell return_address) {
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switch (call_site_opcode(return_address)) {
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case jmp_opcode:
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return true;
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case call_opcode:
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return false;
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default:
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abort();
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return false;
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}
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}
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inline static unsigned int fpu_status(unsigned int status) {
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unsigned int r = 0;
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if (status & 0x01)
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r |= FP_TRAP_INVALID_OPERATION;
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if (status & 0x04)
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r |= FP_TRAP_ZERO_DIVIDE;
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if (status & 0x08)
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r |= FP_TRAP_OVERFLOW;
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if (status & 0x10)
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r |= FP_TRAP_UNDERFLOW;
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if (status & 0x20)
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r |= FP_TRAP_INEXACT;
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return r;
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}
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}
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